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REPORT of 

DRAFT GEAR TESTS 

United States Railroad Administration 
Inspection and Test Section 



Preface by 

C. B. YOUNG, Manager 

Inspection and Test Section, Division of Operation, 
United States Railroad Administration 



Published by the 

Simmons-Boardman Publishing Company 



NEW YORK 
1921 



TF4-I3 
•XL (*5* 



401 7 



ld2i 




CONTENTS 

Page 
Draft Gear Tests of the United States Railroad Administration, Inspection and 

Test Section 1 

Draft Gear Testing 3 

Test Program 6 

Description of Gears 7 

Westinghouse Type D-3, Gears No. 1, 2 and 3 7 

Westinghouse Type NA-1, Gears No. 4, 5, 6, 7 and 8 8 

Sessions Type K, Gears No. 9, 10, 11 and 12 9 

Sessions Jumbo, Gears No. 13, 14 and 15 10 

Cardwell Type G-25-A, Gears No. 16, 17 and 18 11 

Cardwell Type G-18-A, Gears No. 19, 20 and 21 12 

Miner Type A-18-S, Gears No. 22, 23 and 24 13 

Miner Type A-2-S, Gears No. 25, 26 and 27 14 

National Type H-l, Gears No. 28, 29 and 30 15 

National Type M-l, Gears No. 31, 32 and 33 16 

National Type M-4, Gears No. 34, 35 and 36 17 

Murray Type H-25, Gears No. 37, 38 and 39 17 

Gould Type 175, Gears No. 40, 41 and 42 19 

Bradford Type K, Gears No. 43, 44, 45, 46 and 47 20 

Waugh Plate Type, Gears No. 48, 49 and 50 21 

Christy, Gears No. 51, 52 and 53 21 

Harvey Friction Springs, Gears No. 54, 55 and 56 23 

A. R. A. Class G Springs, Gears No. 57, 58 and 59 23 

Selection and Condition of Test Gears 24 

Westinghouse D-3, Gears No. 1, 2 and 3 24 

Westinghouse NA-1, Gears No. 4, 5, 6, 7 and 8 24 

Sessions K, Gears No. 9, 10, 11 and 12 24 

Sessions Jumbo, Gears No. 13, 14 and 15 25 

Cardwell G-25-A, Gears No. 16, 17 and 18 25 

Cardwell G-18-A, Gears No. 19, 20 and 21 25 

Miner A-18-S, Gears No. 22, 23 and 24 25 

Miner A-2-S, Gears No. 25, 26 and 27 25 

National H-l, Gears No. 28, 29 and 30 26 

National M-l, Gears No. 31, 32 and 33 26 

National M-4, Gears No. 34, 35 and 36 26 

Murray H-25, Gears No. 37, 38 and 39 26 

Gould 175, Gears No. 40, 41 and 42 26 

Bradford K, Gears No. 43, 44, 45, 46 and 47 26 

Christy, Gears No. 51, 52 and 53 27 

Harvey Friction Springs, 8 in. x 8 in., Gears No. 54, 55 and 56 27 

A. R. A. Class G Springs, Gears No. 57, 58 and 59 27 

9,000 Lb. Drop Tests 29 

Westinghouse D-3, Gears No. 1, 2 and 3 30 

Westinghouse NA-1, Gears No. 4, 5, 6, 7 and 8 30 

Sessions K, Gears No. 9, 10, 11 and 12 30 

Sessions Jumbo, Gears No. 13, 14 and 15 30 

Cardwell G-25-A, Gears No. 16, 17 and 18 30 

Cardwell G-18-A, Gears No. 19, 20 and 21 31 

V 



Page 

Miner A-18-S, Gears No. 22, 23 and 24 31 

Miner A-2-S, Gears No. 25, 26 and 27 31 

National H-l, Gears No. 28, 29 and 30 31 

National M-l, Gears No. 31, 32 and 33 31 

National M-4, Gears No. 34, 35 and 36 31 

Murray H-25, Gears No. 37, 38 and 39 32 

Gould 175. Gears No. 40, 41 and 42 . 32 

Bradford K, Gears No. 43, 44, 45, 46 and 47 32 

Waugh Plate Type, Gears No. 48, 49 and 50 32 

Christy, Gears No. 51, 52 and 53 32 

Harvey 8 in. x 8 in. Springs, Gears No. 54, 55 and 56 32 

A. R. A. Class G Springs, Gears No. 57, 58 and 59 33 

Summary of 9,000 lb. Drop Tests 33 

Static Tests 36 

Westinghouse D-3, Gears No. 1 and 2 37 

Westinghouse NA-1, Gears No. 4 and 5 . . 37 

Sessions K, Gears No. 9 and 10 37 

Sessions Jumbo, Gears No. 13 and 14 38 

Cardwell G-25-A, Gears No. 16 and 17 38 

Cardwell G-18-A, Gears No. 19 and 20 38 

Miner A-18-S, Gears No. 22 and 23 , 38 

Miner A-2-S, Gears No. 25 and 26 38 

National H-l, Gears No. 28 and 29 38 

National M-l, Gears No. 31 and 32 39 

National M-4, Gears No. 34 and 35 39 

Murray H-25, Gears No. 37 and 38 39 

Gould 175, Gears No. 40 and 41 39 

Bradford K, Gears No. 45 and 46 39 

Waugh Plate Type, Gears No. 48 and 49 39 

Christy, Gears No. 51 and 52 39 

Harvey 8 in. x 8 in. Springs, Gears No. 54, 55 and 56 40 

A. R. A. Class G Springs, Gears No. 57, 58 and 59 40 

Summary of Static Tests 40 

9,000 Lb. Drop Tests, Friction Surfaces Coated with Foreign Material 62 

Destructive Tests 66 

Westinghouse D-3!, Gear No. 1 66 

Westinghouse NA-1, Gear No. 6 66 

Sessions K, Gear No. 10 ' 67 

Sessions Jumbo, Gear No. 13 67 

Cardwell G-25-A, Gear No. 16 67 

Cardwell G-18-A, Gear No. 19 67 

Miner A-18-S, Gear No. 22 68 

Miner A-2-S, Gear No. 25 68 

National H-l, Gear No. 28 68 

National M-l, Gear No. 31 69 

National M-4, Gear No. 34 69 

Murray H-25, Gear No. 37 69 

Gould 175, Gear No. 40 69 

VI 



Page 

Bradford K, Gear No. 45 70 

Waugh Plate Type, Gear No. 48 70 

Christy, Gear No. 51 70 

Harvey Springs, Gear No. 54 70 

A. R. A. Class G Springs, Gear No. 57 70 

Summary of Destructive Tests 72 

Rivet Shearing Tests 73 

Car-Impact Tests 79 

The Symington Test Plant 79 

Action of Cars During Impact 83 

Records in Car-Impact Tests 87 

Impact Velocity 88 

Travel of Cars Along Track 88 

Draft Gear Travel and Action 88 

Seismograph Readings 89 

Graphs of Car Action 91 

Making a Test Run 91 

Study of Curves 99 

Car-Movement Curves — Superimposed 99 

Velocity Curves 100 

Energy Curves • 102 

Time-Force Curves 103 

Time-Closure Curves 105 

Force-Closure Curves 105 

Solid Buffer Runs 106 

Discussion of Gears in Car-Impact Tests Ill 

National H-l, Gear No. 29 in Car B, 

Gear No. 30, or Solid Buffer, in Car A Ill 

Sessions Type K, Gear No. 11 in Car B, 

Gear No. 12, or Solid Buffer, in Car A .- Ill 

Miner A-18-S, Gear No. 23 in Car B, 

Gear No. 24, or Solid Buffer, in Car A 112 

Westinghouse NA-1, Gear No. 7 in Car B, 

Gear No. 8, or Solid Buffer, in Car A 112 

National M-l, Gear No. 32 in Car B, 

Gear No. 33, or Solid Buffer, in Car A 113 

Sessions Jumbo, Gear No. 14 in Car B, 

Gear No. 15, or Solid Buffer, in Car A 113 

National M-4, Gear No. 35 in Car B, 

Gear No. 36, or Solid Buffer, in Car A 114 

Cardwell G-18-A, Gear No. 20 in Car B, . . 

Gear No. 21, or Solid Buffer, in Car A 114 

Cardwell G-25-A, Gear No. 17 in Car B, 

Gear No. 18, or Solid Buffer, in Car A 114 

Westinghouse D-3, Gear No. 2 in Car B, 

Gear No. 3, or Solid Buffer, in Car A 115 

Gould 175, Gear No. 41 in Car B, 

Gear No. 42, or Solid Buffer, in Car A '. . . 115 

VIT 



Murray H-25, Gear No. 38 in Car B, Page 

Gear No. 39, or Solid Buffer, in Car A 115 

Christy, Gear No. 52 in Car B, 

Gear No. 53 or Solid Buffer in Car A 116 

Miner A-2-S,. Gear No. 26 in Car B, 

Gear No. 27, or Solid Buffer, in Car A 116 

Waugh Plate Type, Gear No. 49 in Car B, 

Gear No. 50, or Solid Buffer, in Car A 117 

Bradford K, Gear No. 46 in Car B, 

Gear No. 47, or Solid Buffer, in Car A 117 

Harvey Springs, Gear No. 55 in Car B, 

Gear No. 56, or Solid Buffer, in Car A 118 

Class G Coil Springs, Gear No. 58 in Car B, 

Gear No. 59, or Solid Buffer, in Car A 118 

Summary of Car-Impact Tests 119 

Comparison of the Different Methods of Testing 129 

General Deductions 132 

Results to be Expected from Commercial Gears 134 

Grading of Average Commercial Gears 139 

Capacity 139 

Smoothness of Action 139 

Ultimate Force or Closing Pressure 139 

Absorption 140 

Over-Solid Sturdiness 140 

Workmanship and General Operation 140 

Service Performance of Gears 140 

State of Development of Gears ". 140 

Service Tests 142 

Train-Operation Tests 143 

Tests of Draft Gear Attachments 143 

Appendices 
Appendix A. Report of Draft Gear Test Made on Norfolk & Western Railroad, 

November 4, 1918 269 

Object of Test 269 

Equipment Used 269 

Preparation of Draft Gears 269 

Recording Apparatus 270 

Discussion of Cards 271 

General 271 

Appendix B. Tests of Car Construction 275 

Test No. 1— Wood Draft Sills 275 

Test No. 2r— Metal Draft Arms 276 

Test No. 3 — Draft Attachments with Central Stop Casting 277 

Condition of Cars 278 

Condition of Coupler and Draft Attachments 278 

Test No. 4 — Attachments with Separate and Independent Draft Lugs 279 

Condition of Cars 280 

Condition of Coupler and Attachments 280 

VIII 



LIST OF ILLUSTRATIONS 

Fig. No. Page 

1 Identification of Gears in Test : 6 

2 Westinghouse D-3 Gear 7 

3 Westinghouse NA-1 Gear 8 

4 Sessions Type K Gear 10 

5 Sessions Jumbo Gear 11 

6 Cardwell Type G-25-A Gear 12 

7 Miner Type A-18-S Gear 13 

8 Miner Type A-2-S Gear 15 

9 National Type M-l Gear 17 

10 Murray Type H-25 Gear 18 

11 Gould Type 175 Gear 19 

12 Bradford Type K Gear 20 

13 Waugh Plate Gear 21 

14 Christy Gear 22 

15 Harvey Friction Springs 23 

16 Comparative Performance of Gears in Drop Tests 34, 35 

17 Comparative Ultimate Resistance of Gears 42, 43 

18 Drop Test and Static Test Diagrams, Westinghouse Type D-3 44 

19 Drop Test and Static Test Diagrams, Westinghouse Type NA-1 45 

20 Drop Test and Static Test Diagrams, Sessions Type K 46 

21 Drop Test and Static Test Diagrams, Sessions Jumbo 47 

22 Drop Test and Static Test Diagrams, Cardwell Type G-25-A 48 

23 Drop Test and Static Test Diagrams, Cardwell Type G-18-A 49 

24 Drop Test and Static Test Diagrams, Miner Type A-18-S 50 

25 Drop Test and Static Test Diagrams, Miner Type A-2-S 51 

26 Drop Test and Static Test Diagrams, National Type H-l 52 

27 Drop Test and Static Test Diagrams, National Type M-l 53 

28 Drop Test and Static Test Diagrams, National Type M-4 54 

29 Drop Test and Static Test Diagrams, Murray Type H-25 55 

30 Drop Test and Static Test Diagrams, Gould Type 175 56 

31 Drop Test and Static Test Diagrams, Bradford Type K 57 

IX 



Fig. No. p AGE 

32 Drop Test and Static Test Diagrams, Waugh Plate Gear 58 

33 Drop Test and Static Test Diagrams, Christy Draft Gear 59 

34 Drop Test and Static Test Diagrams, Harvey Friction Springs 60 

35 Drop Test and Static Test Diagrams, A. R. A. Class G Springs 6L 

36 Performance of Gears with Coated Friction Surfaces (Drop Test) 63 

37 Drop Tests of Friction Gears Which Were Taken Out of Service, 

Norfolk & Western Railway 64 

38 Performance of Gears in Destructive Tests 71 

39 Results of i/ 2 in. Rivet Shearing Tests. Draft Gears for U. S. R. A. 

Cars. 9,000-lb. Drop 74 

40 Performance of Gears in V 2 in. Rivet Shearing Tests. 9,000-lb. Drop . . 75 

41 Diagrams of Rivet Shearing Action of Draft Gears 77 

42 General View of Symington Gravity Test Plant 80 

43 General Profile of Test Track 81 

44 Enlarged Profile of Test Track for 90 ft 82 

45 Enlarged Profile for 12-in. Movement of Car A 83 

46 Enlarged Profile for 12-in. Movement of Car B 83 

47 General View of Car B and Its Lading 84 

48 Farlow Two-Key Draft Gear Attachments Used on Test Cars 85 

49 Instrument on Car B for Recording Draft Gear Action 90 

50 Specimen Time-Closure Curve Produced on Small Drum of Car B . . . . 89 

51 Seismograph of Car A 91 

52 Instrument for Recording Car Action 92 

53 Another View of Instrument for Recording Car Action 93 

54 Specimen Car-Movement Card from Drum A 95 

55 Specimen Car-Movement Card from Drum B 95 

56 Specimen Car-Movement Cards from Drums A and B Superimposed. . 97 

57 Mechanical Differentiating Machine 103 

58 Curves from Solid Buffer Runs 108 

59 Plot of Car Body Yield at Varying Impact Velocities 109 

60 Plot of Force at Varying Impact Velocities 110 

61 Tabulation of Closing Speeds of Gears; Car-Impact Tests 121 

62 Tabulation of Car-Impact Tests — Closing Speed Runs. Double Gear 

Tests, 143,000-lb. Cars 122, 123 

63 Tabulation of Car-Impact Tests, One-Mile-Per-Hour Runs. Double 

Gear Tests 124, 125 

X 



Fig. No. Page 

64 Tabulation of Car-Impact Tests, Closing Speed Runs. Single Gear 

Tests, 143,000-lb. Cars 126, 127 

65 Comparison of Double Gear and Single Gear Action. Car Impact 

Tests. 143,000-lb. Cars 128 

66 Comparison of Work Done and Work Absorbed by Test Gears in Static, 

Drop and Car-Impact Tests 131 

67 Comparative Performance of Commercial Gears, Showing Average Re- 

sults that may be Expected from New Gears of Each Type . . . 136, 137 

68 Energy Curves for Cars of Various Weights, with Commerical Gear 

Capacities Indicated 138 

69 Grading of Gears, Based Upon Performance of New Commercial Gears 141 

70 List of and Index of Car-Movement Curves and Derivative Curves, Em- 

bracing Figs. 71 (a to t) to 88 (a to t) Inclusive 144 

71a Car-Movement Curves, Superimposed, National H-l Gears 145 

71b-c Car-Movement Curves, Superimposed, National H-l Gears 146 

71d-e-f Velocity Curves, National H-l Gears 147 

71g-j Energy Curves, National H-l Gears 148 

71k-m Time-Force Curves, National H-l Gears 149 

71n-q Time-Closure Curves, National H-l Gears 150 

71r-t Force-Closure Diagrams, National H-l Gears 151 

72a Car-Movement Curves, Superimposed. Sessions K Gears 152 

72b-c Car-Movement Curves, Superimposed. Sessions K Gears 153 

72d-e-f Velocity Curves, Sessions K Gears '. 154 

72g-j Energy Curves, Sessions K Gears 155 

72k-m Time-Force Curves, Sessions K Gears 156 

72n-p-q Time-Closure Curves, Sessions K Gears 157 

72r-t Force-Closure Diagrams, Sessions K Gears 158 

73a Car-Movement Curves, Superimposed. Miner A-18-S Gears 159 

73b-c Car-Movement Curves, Superimposed. Miner A-18-S Gears 160 

73d-e-f Velocity Curves, Miner A-18-S Gears 161 

73g-j Energy Curves, Miner A-18-S Gears 162 

73k-m Time-Force Curves, Miner A-18-S Gears 163 

73n-p-q Time-Closure Curves, Miner A-18-S Gears 164 

73r-t Force-Closure Diagrams, Miner A-18-S Gears 165 

74a Car-Movement Curves, Superimposed. Westinghouse NA-1 Gears . . . 166 

74-b-c Car-Movement Curves, Superimposed. Westinghouse NA-1 Gears.... 167 

XI 



Fig. No. Page 

74d-e-f Velocity Curves, Westinghouse NA-1 Gears 168 

74g-j Energy Curves, Westinghouse NA-1 Gears 169 

74k-m Time-Force Curves, Westinghouse NA-1 Gears 170 

74n-q Time-Closure Curves, Westinghouse NA-1 Gears 171 

74r-t Force-Closure Diagrams, Westinghouse NA-1 Gears 172 

75a Car-Movement Curves, Superimposed, National M-l Gears 173 

75b-c Car-Movement Curves, Superimposed. National M-l Gears 174 

75d-e-f Velocity Curves, National M-l Gears 175 

75g-j Energy Curves, National M-l Gears 176 

75k-m Time-Force Curves, National M-l Gears 177 

75n-q Time-Closure Curves, National M-l Gears 178 

75r-t Force-Closure Diagrams, National M-l Gears 179 

76a Car-Movement Curves, Superimposed. Sessions Jumbo Gears 180 

76b-c Car-Movement Curves, Superimposed. Sessions Jumbo Gears 181 

76d-e-f Velocity Curves, Sessions Jumbo Gears 182 

76g-j Energy Curves, Sessions Jumbo Gears 183 

76k-m Time-Force Curves, Sessions Jumbo Gears 184 

76n-p-q Time-Closure Curves, Sessions Jumbo Gears 185 

76r-t Force-Closure Diagrams, Sessions Jumbo Gears 186 

77a Car-Movement Curves, Superimposed. National M-4 Gears . 187 

77b-c Car-Movement Curves, Superimposed. National M-4 Gears 188 

77d-e-f Velocity Curves, National M-4 Gears 189 

77g-j Energy Curves, National M-4 Gears 190 

77k-m Time-Force Curves, National M-4 Gears 191 

77n-q Time-Closure Curves, National M-4 Gears 192 

77r-t Force-Closure Diagrams, National M-4 Gears 193 

78a-b Car-Movement Curves, Superimposed. Cardwell G-18-A Gears 194 

78c Car-Movement Curves, Superimposed. Cardwell G-18-A Gears 195 

78d-e-f Velocity Curves, Cardwell G-18-A Gears 196 

78g-j Energy Curves, Cardwell G-18-A Gears 197 

78k-m Time-Force Curves, Cardwell G-18-A Gears 198 

78n-q Time-Closure Curves, Cardwell G-18-A Gears 199 

78r-t Force-Closure Diagrams, Cardwell G-18-A Gears 200 

79a Car-Movement Curves, Superimposed. Cardwell G-25-A Gears 201 

XII 



Fig. No. Page 

79b-c Car-Movement Curves, Superimposed. Cardwell G-25-A Gears 202 

79d-e-f Velocity Curves, Cardwell G-25-A Gears 203 

79g-h-j Energy Curves, Cardwell G-25-A Gears 204 

79k-l-m Time-Force Curves, Cardwell G-25-A Gears 205 

79n-p-q Time-Closure Curves, Cardwell G-25-A Gears 206 

79r-s-t Force-Closure Diagrams, Cardwell G25-A Gears 207 

80a Car-Movement Curves, Superimposed. Westinghouse D-3 Gears 208 

80b-c Car-Movement Curves, Superimposed. Westinghouse D-3 Gears .... 209 

80d-e-f Velocity Curves, Westinghouse D-3 Gears 210 

80g-h-j Energy Curves, Westinghouse D-3 Gears 211 

80k-l-m Time-Force Curves, Westinghouse D-3 Gears 212 

80n-p-q Time-Closure Curves, Westinghouse D-3 Gears 213 

80r-s-t Force-Closure Diagrams, Westinghouse D-3 Gears 214 

81a Car-Movement Curves, Superimposed. Gould No. 175 Gears 215 

81b-c Car-Movement Curves, Superimposed. Gould No. 175 Gears 216 

81d-e-f Velocity Curves, Gould No. 175 Gears 217 

81g-h-j Energy Curves, Gould No. 175 Gears 218 

81k-l-m Time-Force Curves, Gould No. 175 Gears 219 

81n-p-q Time-Closure Curves, Gould No. 175 Gears 220 

81r-s-t Force-Closure Diagrams, Gould No. 175 Gears 221 

82a Car-Movement Curves, Superimposed. Murray H-25 Gears 222 

82b-c Car-Movement Curves, Superimposed. Murray H-25 Gears 223 

82d-e-f Velocity Curves, Murray H-25 Gears 224 

82g-h-j Energy Curves, Murray H-25 Gears 225 

82k-l-m Time-Force Curves, Murray H-25 Gears 226 

82n-p-q Time-Closure Curves, Murray H-25 Gears 227 

82r-t-s Force-Closure Diagrams, Murray H-25 Gears 228 

83a Car-Movement Curves, Superimposed. Christy Gears 229 

83b-c Car-Movement Curves, Superimposed. Christy Gears 230 

83d-e-f Velocity Curves, Christy Gears 231 

83g-j Energy Curves, Christy Gears 232 

83k-m Time-Force Curves, Christy Gears 233 

83n-q Time-Closure Curves, Christy Gears 234 

83r-t Force-Closure Diagrams, Christy Gears 235 

84a Car-Movement Curves, Superimposed. Miner A-2-S Gears 236 

XIII 



Fig. No. Page 

84b-c Car-Movement Curves, Superimposed. Miner A-2-S Gears 237 

84d-e-f Velocity Curves, Miner A-2-S Gears 238 

84g-j Energy Curves, Miner A-2-S Gears 239 

84k-m Time-Force Curves, Miner A-2-S Gears 240 

84n-p-q Time-Closure Curves, Miner A-2-S Gears 241 

84r-t Force-Closure Diagrams, Miner A-2-S Gears 242 

85a-b-c Car-Movement Curves, Superimposed. Waugh Plate Gears 243 

85d-e-f Velocity Curves, Waugh Plate Gears 244 

85g-j Energy Curves, Waugh Plate Gears 245 

85k-m Time-Force Curves, Waugh Plate Gears 246 

85n-p-q Time-Closure Curves, Waugh Plate Gears 247 

85r-t Force-Closure Diagrams, Waugh Plate Gears 248 

86a-b-c Car-Movement Curves, Superimposed. Bradford K Gears 249 

86d-e-f Velocity Curves, Bradford K Gears 250 

86g-j Energy Curves, Bradford K Gears 251 

86k-m Time-Force Curves, Bradford K Gears 252 

86n-p-q Time-Closure Curves, Bradford K Gears 253 

86r-t Force-Closure Diagrams, Bradford K Gears 254 

87a-b-c Car-Movement Curves, Superimposed, Harvey Springs 255 

87d-e-f Velocity Curves, Harvey Springs 256 

87g-j Energy Curves, Harvey Springs 257 

87k-m Time-Force Curves, Harvey Springs 258 

87n-p-q Time-Closure Curves, Harvey Springs 259 

87r-t Force-Closure Diagrams, Harvey Springs 260 

88b-c Car-Movement Curves, Superimposed. A. R. A. Class G Springs 261 

88e-f Velocity Curves, A. R. A. Class G Springs 262 

88j Energy Curve, A. R. A. Class G Springs 263 

88m Time-Force Curves, A. R. A. Class G Springs 263 

88p-q Time-Closure Curves, A. R. A. Class G Springs 264 

88t Force-Closure Diagram, A. R. A. Class G Springs 265 

89-1 Summary Curves, Westinghouse D-3 Gears 266 

89-2 Summary Curves, Westinghouse D-3 Gears 267 

89-3 Summary Curves, Westinghouse D-3 Gears 268 

Chronographic Records of Draft Gear Action in Train Service, Norfolk 

& Western Railway 273, 274 

XIV 



PREFACE 

When the United States Railroad Administration decided in the spring of 1918 to enter upon 
its car and locomotive building program, one of the problems which early came before the Com- 
mittee on Standards for Locomotives and Cars and the Central Advisory Purchasing Committee 
was the selection of draft gears to be used and the allocation of orders among the several manu- 
facturers. The Committee on Standards and the Purchasing Section were both embarrassed, 
owing to a lack of definite and positive knowledge as to the relative merits of the different gears 
as well as the relation between mechanical value and cost. Much information on the subject of 
draft gears was presented by the various manufacturers, but a comparison of the information 
presented soon developed the fact that each manufacturer had prepared his information on a basis 
of his own selection and that it was impossible to correlate or co-ordinate the various tests in any 
comparable manner. The reports of the Draft Gear Committee of the Master Car Builders' Associa- 
tion and the files of the mechanical associations failed to give any definite information on the 
subject. 

In the absence of real information, the Committee on Standards adopted the wording of the 
M.C.B. specification for draft gears for Class III and Class IV tank cars which provides that the 
gears purchased shall have a "minimum capacity of 150,000 lb." The committee later defined this 
requirement in the following words: 

"A 150,000 lb. draft gear should be defined as one that will sustain a drop of 
16 in. (including travel of the gear) of a 9,000 lb. weight without shearing the rivets 
of one or both lugs which are to be secured to suitable members by nine V2 in. rivets 
of .15 carbon or under, driven in -ft in. holes." 

When gears were tested under this requirement, it was found that no useful information was 
obtained. Gears of widely varying characteristics and excellence passed the prescribed test and 
it was soon appreciated that the specification requirement as well as this test were useless in 
obtaining draft gear information. 

When this absolute dearth of reliable knowledge on the subject was fully realized by the 
Committee on Standards and the Purchasing Committee, they joined in requesting the Inspection 
and Test Section of the Division of Operation to conduct such a series of tests as would determine 
the mechanical value of each make and type of friction draft gear then regularly offered for sale 
to railroads. 

In addition to the various tests which have been completed and which are given in the report, 
the Section had definite plans made for train operation tests and service tests. Had the time been 
available and had circumstances permitted, the Section would have completed these tests. 

It is much to be regretted that conditions on the railroads throughout the country during the 
war and immediately thereafter prevented the carrying out of these tests and this, to a degree, 
operates to render the present work inconclusive. 

The information covering the tests which have been made on new gears is definite and final. 
To a limited degree, tests were made on gears which had seen considerable service but the 
service tests themselves and the train operation tests were not made for the reasons given. 

It is much to be hoped that arrangements will be made to complete the full series outlined by 
the Section and thereby render available accurate information concerning the action of gears in 
train operation and the ability of each type of gear to stand up in service. With this added 
information, mechanical officers and purchasing agents would be able to equate value and cost and 
to understandingly purchase a definite amount of protection for a definite amount of money. 



If the present report does no more, it gives reliable and entirely comparable and unbiased 
values for new commercial gears of the various types. The values given should supplant the 
widely variant figures frequently given out in the past as a result of inaccurate, unscientific or 
incomparable tests. 

Attention should be called to the fact that this report must be used as a whole in order to 
obtain accurate and definite information concerning the draft gears. The picking out and exploit- 
ing of an idea shown here or there throughout the test and which favors one or the other of the 
draft gears tested, should be heartily discouraged and those who use the report should guard them- 
selves against errors of this kind. The pros and cons of all gears must be thoroughly balanced 
by those who are looking for the truth. 

In the chapter entitled "Grading of Average Commercial Gears" will be found the only place 
where personal opinion has in any manner entered into the report. The assignment of the number 
of points of excellence to the various functions of the gears is on the basis of the ideal gear and 
engineers who study the work may not entirely agree with this assignment. 

Attention is also called to the fact that on plate 69 where these points of excellence are used 
to rate the various gears, a column covering wearing qualities has not been included. Engineers 
will, of necessity, record their opinions and observations as to wearing qualities and in so doing 
may materially change the grading of the gears as shown on this table. 

In making these tests the path was entirely unbroken, the trail was unblazed. It was necessary 
to avoid many previous methods of testing that are erroneous and misleading. It was also 
necessary to forget at the outset the values of the several gears as generally reported and accepted. 
It was necessary to lay aside all prejudices and personal preferences. 

With one or two exceptions the tests were welcomed by the draft gear manufacturers, and 
their full co-operation was freely given. 

The importance of the type and design of the draft gear attachments is often not fully 
appreciated. The report covering the tests of attachments and of reinforced and unreinforced 
wooden car construction gives, probably for the first time, reliable figures for the comparison of 
these features of construction, and also gives some slight hint of the wealth of information on 
general car construction that can be developed from actual impact tests, if carefully made and 
reported. 

Acknowledgment is made of the services and hearty co-operation of Messrs. B. W. Kadel, 
E. M. Richards and L. H. Schlatter in the active conduct of the test in the field as well as the 
working up of the data contained herein. 

C. B. YOUNG, 

Manager of the Inspection and Test Section of the 
Railroad Administration during Federal Control. 

Chicago, 111., 

January 20, 1921. 



DRAFT GEAR TESTS OF THE U. S. RAILROAD ADMINISTRATION, 
INSPECTION AND TEST SECTION 



The draft gear tests of the United 
States Railroad Administration were origi- 
nally undertaken at the request of the Com- 
mittee on Standards for Locomotives and 
Cars and the Central Advisory Purchasing 
Committee for the purpose of determining 
the relative merits of the several com- 
mercial gears in order that mechanical ex- 
cellence and costs might be evaluated. The 
Inspection and Test Section, as a prelim- 
inary to any work, carefully studied all 
of the common methods of testing draft 
gears. Letters on the general subject were 
also addressed by the section to all of the 
draft gear manufacturers and to a large 
number of prominent mechanical officers 
of the roads, the replies to which showed 
a wide difference of opinion, not only as 
to the proper method of testing draft gears, 
but as to what performance should be ex- 
pected from a gear. 

A comparison of the many test reports 
submitted, showed an entire inconsistency 
in results, supposedly obtained under sim- 
ilar conditions. It became evident that 
a test of all gears under exactly the same 
conditions, removed from any proprietary 
influence, was essential, and also that the 
tests should be conducted in such a man- 
ner as not only to determine the compara- 
tive value of the several gears, but to ob- 
tain all the exact information possible with 
respect to draft gear action, and to ex- 
tend the study as far as possible toward 
the ultimate determination of the ideal 
draft gear. With such a program in view, 
the co-operation of the A. R. A. Committee 
on Draft Gears was felt to be desirable, 
and upon invitation from this section, this 
committee has taken an active part in the 



test work and in analyzing and compiling 
the results. 

The present report covers in a rather ex- 
tensive manner the action and comparative 
merits of the various gears when con- 
sidered from the viewpoint of impact and 
buffing. The opportunity for the investiga- 
tion of draft gears in train starting and sim- 
ilar operations has not developed as was 
hoped for, so that it is impossible at this 
time to present definite information in this 
latter respect. It is desired accordingly, 
that this report, which compares the sev- 
eral commercial gears and deals extensively 
with the question of cushioning and absorb- 
tion, shall be considered only as a part of 
an extended investigation into the action 
of draft gears, not only in buffing and im- 
pact, but also in train starting and hand- 
ling. 

The full investigation of draft gears 
should include not only,the laboratory and 
impact tests of the present report, but also 
a wide range of train operation tests and 
service tests, from the results of which 
should ultimately be determined: 

1. The minimum amount of movement 
necessary between cars for starting trains, 
and whether this movement may be free 
slack, as between coupler knuckles, or 
whether it should be resisted movement. 

2. Whether the beginning of draft gear 
compression should be an easy movement 
or a stiff movement, and whether there 
should be an initial compression to prevent 
movement from slight shocks. 

3. The effects of recoil and what amount 
of release force is desirable. 



— 1 — 



2 



Draft Gear Tests of the U. S. Railroad Administration 



4. The desired capacity, travel, and ulti- 
mate resistance of the gear, as well as the 
shape of the curve representing draft gear 
resistance for both buffing and train start- 
ing. 

5. The coupler horn clearance and coup- 
ler shank clearance. 



6. The life, together with the rate of 
wear and loss in gear capacity attending 
it, that should be expected from an accept- 
able draft gear, as well as the setting of a 
measure, either in time, mileage, or loss of 
capacity, when a draft gear should be re- 
moved from the car and be repaired or 
scrapped. 



DRAFT GEAR TESTING 



The following discussion on the general 
subject of draft gear testing is given for 
the benefit of any who may be called upon 
to do similar work in the future. 

It is important to have a full knowledge 
of the condition of each test gear before 
putting it into a test. Check measure- 
ments should be made, such as spring 
heights, barrel or housing dimensions, in- 
itial spring compression, initial friction 
compression, absolute free height, absolute 
friction height, and solid height, keeping 
a record of possible travel at any of the 
previously mentioned gear heights. By 
having such a record it will later be pos- 
sible to check up the gear conditions and 
to know whether any loss in travel is due 
to set of springs, wear of friction mem- 
bers or deformation of parts of the gear. 
Depreciation in any of these respects 
should be reported in equivalent loss in 
coupler or gear travel. 

It is important to protect the friction 
surfaces of test gears from any grease, rust 
or moisture. Even the handling of the 
friction faces with bare hands may leave 
enough grease or moisture on them to 
lower the gear capacity. After taking a 
new gear apart it should be reassembled 
with the parts always in their original re- 
lationship, and the gear should then be 
operated not less than ten times before mak- 
ing a regular test. Any rust on the fric- 
tion surfaces should be removed by sand 
papering, and the gear should then be oper- 
ated not less than twenty times if compara- 
ble and consistent results are to be ob- 
tained. This does not mean that the fric- 
tion faces of draft gears do not have de- 
posits of rust and other foreign material 
on them in service, but is given as a rule 



for conducting comparative tests of new 
gears. 

In testing draft gears, the gear should 
not be loaded beyond the solid point. Few 
gears will stand much service beyond their 
normal capacities, especially under the 
drop machine. The determination of the 
solid point, however, is often quite diffi- 
cult. Sometimes the spring coils, or other 
internal gear parts, will go solid be- 
fore the gear is fully closed. The 
result is that a greater load or drop is 
required to fully close the external 
portions of the gear than would be re- 
quired if normal action obtained through- 
out. The static test is best suited to accur- 
ately fix the limit of normal gear closure. 
In tests of other characters, such as the 
drop test, the gear should be closed only 
to the travel determined from the static 
cards as the limit of normal gear action. 

All gears, irrespective of construction, 
should be set up and restrained in a suit- 
able testing frame, corresponding in dimen- 
sions to the draft gear pocket in the car. 
The frame should be so designed that the 
influence of its yield will be minimized, 
The gear should rest in the frame upon 
pieces of metal corresponding to the stop 
faces of the gear draft lugs or other stop 
member. A striking plate of the same size 
as the coupler butt should be placed on 
top of the gear for receiving the blow. This 
will develop whether or not the gear con- 
struction is substantial enough to receive 
the coupler butt forces in service. Where 
followers are regularly used with a gear, 
they should, for comparative purposes, be 
set up with the gear in the testing frame. 
In all respects service conditions should be 
simulated in the testing frame, as in no 



— 3 — 



4 



Draft Gear Tests of the U. S. Railroad Administration 



other manner will the weak or strong points 
of a gear be shown. It is more convenient 
to test gears such as the Miner, Westing- 
house and similar types without a frame, 
but a frame is necessary for some other 
gears, such as the Cardwell, and in any 
impact testing the yield of the frame, no 
matter how carefully constructed, may 
slightly increase the results. It is there- 
fore only fair that all gears should be 
tested under similar conditions. 

On the subject of heating but little needs 
to be said. It is not often that a gear will 
be operated fast enough to heat it suffi- 
ciently to affect the results unless a wear 
test or endurance test is being made. In 
such a test the gear should not be allowed 
to become more than just warm to the 
hand. 

It is a noticeable fact, however, that if 
a friction gear is brought for testing from 
a cold place into a warm room, the capacity 
will be low; and if brought from a warm 
room to a colder outside atmosphere, 
the capacity will be higher. This is due 
to the deposit of moisture on the colder 
metal, or the abstraction of moisture from 
the friction surfaces of the warmer metal, 
as the case may be. In general the hu- 
midity of the air is a decided factor in 
testing, and an instance is known of a de- 
preciation of 20 per cent in a gear which 
could be explained in no other manner. 

Another point of interest is that when a 
gear is to be given a static test without a 
frame, and the free height of the gear is 
greater as set up than the pocket length in 
the car, the gear should first be compressed 
to slightly below the pocket dimension and 
then released to the exact pocket length. 
The compression test should then start 
from this released point. 

In impact testing, where the load passing 
through the gear to the supporting device 
is measured or compared, the gear should 



never be tested beyond the closing point. 
This rule applies particularly to rivet 
shearing tests and oar-impact tests. It 
should be remembered that after a gear 
goes solid its normal functioning ceases, 
and further testing is only of the gear 
housings or barrel. Hence in over-solid 
testing the greater deformation of a weaker 
gear barrel offers additional protection to 
the rivets for the time being, and also offers 
more yield in the car tests. Any consider- 
able repetition of such over-solid blows 
would, however, shortly destroy the gear. 
On the other hand, a sturdy gear will usu- 
ally shear the rivets at the first over-solid 
blow and will similarly produce a sudden 
change in car velocity, but the sturdy gear 
will not be so quickly destroyed. In prac- 
tice, no one would knowingly use a weak 
draft gear in order to protect draft lug 
rivets, but draft gear tests are frequently 
made with this object in view. A weak 
gear barrel will show up well enough 
for the few over-solid blows given it in a 
laboratory, but will shortly be depreciated 
or destroyed from the repetition of such 
blows as occurs in service. In fact, if a 
gear of sturdy design should shear the % 
in. rivets at say a total fall of 16 in., it 
would be entirely practical to increase this 
figure several inches by simply reducing 
the thickness of the barrel or other part 
receiving the solid blow. For a full knowl- 
edge of the functioning of a gear it is neces- 
sary to know only its capacity up to the 
point of closure and the character of its 
action within that capacity. Any yield or 
cushioning beyond the solid point is due 
to deformation or spring of the heads or 
barrel, and is obtained only at the ex- 
pense of strength and life of the gear. 

The suggestion is frequently made that 
all gears be tested to determine the point 
where a force of say 500,000 lb. is set up 
in the sills. On the face this would appear 



Draft Gear Tests of the U. 5. Railroad Administration 



to be entirely reasonable and a proper test 
for the grading of gears. But for the same 
reasons as before, a premium would be 
placed upon a weak gear construction. 
Furthermore, it is a fundamental principle 
of mechanics that there can be no force set 
up in any structure greater than the re- 
sistance offered by the structure. It there- 
fore follows that if a gear were constructed 
with an ultimate strength value of 400,000 
lb. it would be physically impossible to 
apply 500,000 lb. through it to the car. 
Hence, the only over-solid draft gear tests 
that should be made are those that will 
discover the weakness of a gear rather than 
credit it with false merit. The destruction 
and endurance tests are the only over-solid 
draft gear tests known that will correctly 
rate the gears in this respect. 



Another practice from which wrong con- 
clusions are often drawn is that of testing 
gears against sills of different sizes and 
conditions. It is not fair to set up one 
gear on heavy channels and another on light 
channels, as again, the force developed 
will depend upon the yield and the resist- 
ance offered by the channels. Thus if a test 
were made upon 20-lb. channels it would 
be unreasonable to expect as high a force as 
upon 30 lb. or 40 lb. channels, for not only 
is there a greater yield of the channel, but 
the elastic limit of the material in the 
lighter channels might be reached and 
passed, which would preclude the possibil- 
ity of reaching as high a force as might 
be shown in the heavier channels. In other 
words, it is impossible to put more load 
into the light channels than they will stand, 
as the force is limited by the resistance of 
the structure supporting the gear. 



THE TEST PROGRAM 



The following general program was de- 
cided upon for the present tests as offering 
the best means of investigating the com- 
parative action of the gears: 

9,000 lb. Drop Tests— Solid Anvil. 

Closing gears by drops of 1 in. in- 
crements. 

Recoil tests. 

Investigation of influence of foreign ma- 
terial on friction surfaces. 

Investigation of rivet shearing tests. 

Destructive tests. 

Static Tests. 

Closing gears at a rate of ]/% in. per 

minute. 
Closing gears at a rate of ^4 m - per 

minute. 
Closing gears at a rate of 3 in. per 

minute. 

Car Impact Tests. 

Calibrated gear in one car only, solid 

buffer in another car. 
Calibrated gears in both cars. 

In general three each of 18 different 
types of draft gears are embraced in the 
tests. The table of Fig. I has been pre- 
pared to identify the gears and to give 
other data of prime interest in connection 
with them. Fifty-nine gears in all were 
used because of gear failures developing 
during the test as follows: 

Westinghouse NA-1 gears No. 4 and No. 
5 failed in the slow static test. 

Sessions K gear No. 9 failed in the slow 
static test. 

Bradford gears No. 43 and No. 44 failed 
in the drop test. 





MAHE AA/O 

TYPE OF 

GEAR 




< *• 
IS 






his 




(7) 


©. 


@ 


G> 


e 


© 


/ 


WESTWGHOUSE 
D-3 


*f 


*tf 


zoo*" 


4- 


684** 


2 


3 


4 


WEST/AftHOUSE 
A/A-/ 


3" 


2*r 


366* 


2 


676 *** 


5 


6 


7 


a 


9 


SESS/OA/S 


*£ 


*°f 


202* 


4 


766** 


/o 


// 


/2 


/3 


SESSIONS 
JUMBO 


3" 


*+f 


433** 





666* 


/4 


IS 


/6 


CARDWELL 
G-2S-A 


*f 


wf 


440** 





300* 


/7 


/a 


/9 
20 


CARDWELL 
S-/6-A 


*4" 


2«f 


440** 


O 


660* 1 


2/ 


22 


M/A/ER 
A-/3-5 


H" 


«*" 


346** 


2 


334* 


23 
24. 


25 


M/A/ER 
A-2-5 


**' 


*of 


207** 


4 


693 


26 


27 


28 


MAT/ONAL 
H-/ 


*/ 


uf 


426** 





656 ** 


29 


30 


3/ 


A/AT/OA/AL 
Af-/ 


H* 


2*f 


372** 





744* 


32 


33 


34 


NAT/OA/AL 
M-4- 


*/ 


24$ 


322** 





644** 


35 


36 


31 


MURRAY 
H-2S 


**" 


*f 


376** 





7S2« 


36 


39 


40 


GOULD 
/7S 


H' 


22? 


337** 


2 


6/6 ** 


4/ 


42 


43 


BRADFORD 


*£ 


?4f 


336 ** 


O 


772 * 


44 


45 


4S 


47 


46 
49 


WAUGH 
PLATE 


*£ 


*f 


420 ** 


o 


960 * 


50 


51 


CHR/STY 


H' 


22? 


442** 


z 


I02.G ** 


52 


53 


54 


HARl/EY 
2'8"x8"SPGS. 


'f 


V 


I04** 


6- if 

Followara 


67 O 


55 


56 


57 


CO/L SPR/N6S 
Z-&8-CLASS 6 


>? 


7f 


//0* 


6- if 

Fallows* 


eez* 


5<S 


59 



Fig. 1 — Identification of Gears in Test 



— 6 — 



DESCRIPTION OF GEARS 



All of the gears in the test, with two 
exceptions, are of such dimensions as to 
go into the standard 9% in. x 12% in. x 
24% in. draft gear pocket and no gears 
were included except such as had been 
developed to the state of being in use, at 
least to a limited extent, on one or more 
railroads. To properly identify the several 
gears a brief description and an analysis 
of each of the types will be given. 

Westinghouse Type D-3 
Gears No. 1, 2 and 3 

This is the well-known friction draft 
gear of the Westinghouse Air Brake Com- 
pany, and is the same gear as applied to 



as wear equivalent to % in. coupler move* 
ment has occurred, the gear and the fric- 
tion members will be loose in the car. 

The malleable iron friction barrel has 
a plurality of V-shaped ways on its in- 
terior surface and the composite segments 
or splines, eight in number, are wedged 
outwardly into these ways to produce fric- 
tional resistance against longitudinal 
movement of the splines. The gear is ar- 
ranged with a pressure-limiting feature, so 
that when a predetermined load has been 
applied to the friction wedge, the follower 
comes directly into contact with the outer 
ends of the splines and additional wedging 
is prevented. On release the friction strips 
are arranged to be started serially so that 




Fig. 2 — Westinghouse D-3 Gear 



25,000 of the United States Railroad Ad- 
ministration cars. It has a nominal travel 
in the car of 2-7/16 in. the first % in. of 
which is spring travel, the remainder be- 
ing friction travel. In addition to this the 
gear is placed in the car under y 8 in. 
initial spring compression. Thus as soon 



sticking will be less likely to occur. No 
provision is made for taking up wear and 
lost motion in this gear. 

Each gear is made up of a total of 32 
parts, 25 of which are subject to wear, 
one of these being the barrel or housing. 
Considerable grinding and other machine 



8 



Draft Gear Tests of the U. S. Railroad Administration 



work is done on this gear so that it may 
be termed a finished gear. It is not self- 
contained but can fall apart when dropped 
from the car, although it is assembled at 
the factory and shipped and applied as a 
single unit. A peculiar feature of this 
gear is that should wear equivalent to % in. 
coupler movement occur, the wedging ac- 
tion would cease except for a slight amount 
resulting from the tapered ways of the 
barrel. After this the gear would be sub- 
stantially a spring draft gear. 

The gear has a friction spring value of 
19,500 lb. and an additional independent 
release spring value of 6,000 lb. The pre- 
liminary spring has an active value of 
14,800 lb. The friction area of this gear 



no additional metal being presented for 
this load. 

The nominal length of the gear is 20% 
in., so that two followers of 2 1 / 4: in. thick- 
ness are required for it. The gears as 
furnished weigh on the average about 200 
lb. each, or 400 lb. per car, to which must 
be added for comparative purposes four 
followers per car, weighing 71 lb. each, 
giving a per car weight for this gear of 
684 lb. 

Westinghouse Type NA-1 

Gears No. 4, 5, 6, 7 and 8 

This new gear of the Westinghouse Air 
Brake Company is made with a cast steel 
barrel of rectangular cross-section. The 



V//////M 



V///^///y-//A A 




Fig. 3 — Westinghouse NA-1 Gear 



increases as the gear closes, additional 
metal of both the moving and the stationary 
elements coming into contact. The solid 
blow on this gear is carried by the same 
metal that resists the frictional movement, 



friction elements comprise one series of 
stationary plates and another series of rela- 
tively movable plates alternating there- 
with, the plates being loaded through a 
set of central wedge members. Four fric- 



Draft Gear Tests of the U. S. Railroad Administration 



tion springs are used, in addition to one 
central release spring. All five of the 
springs are duplicate and the gear has a 
friction spring value of approximately 
17,000 lb. plus an additional release spring 
value of approximately 4,300 lb. 

This gear has an absolute free length of 
23-7/32 in. and is held to a compressed 
normal length of 22% in. by means of a 
key arrangement. The gear is thus under 
an initial compression of 27/32 in. in the 
car. The first 7/64 in. of this is spring 
compression and the remainder is friction 
compression. This means that the friction 
elements can wear an amount equal to 
47/64 in. coupler travel before the friction 
parts of the gear become loose. The ca- 
pacity of the gear, however, will begin to 
depreciate as soon as any wear takes place. 
The gear has a nominal travel in service 
of 3 in. 

The parts of the gear are held, when 
new, in compressed position by means of 
the key arrangement and hence the gear 
is self-contained. Wear of the friction 
parts, however, will cause the movable 
friction plates to loosen, so that they can 
be lifted out of the gear barrel. Consid- 
erable fitting and grinding is done in the 
manufacture of this gear. There are a 
total of 28 pieces per gear, 12 of which 
are subject to wear, these latter being small 
parts, however, and easily renewable. 
There is no wear on the barrel of this gear 
and no wear at any point that cannot be 
compensated for by the insertion of simple 
plate liners. Any permanent set or short- 
ening of the friction springs will produce 
loss of capacity and slack and this cannot 
be taken up by the liners. 

The friction area of this gear is constant 
for all points of its travel, the pressure per 
square inch increasing as the gear is com- 
pressed. On the stationary friction ele- 
ments the same area is in engagement at 
all times. The engagement portions of the 



moving plates change at all points of the 
travel of the gear. The solid blow comes 
on the side walls of this gear, at places 
not highly loaded by the frictional resis- 
tance of the gear, so that for the solid blow 
at least some additional metal is presented. 
The gear as manufactured is 22% in. 
long, so that one 2^ in. follower is re- 
quired with it. These gears as furnished 
weigh on the average about 368 lb. each, 
or 736 lb. per car, to which, for compara- 
tive purposes must be added two followers 
per car, weighing 71 lb. each, giving a per 
car weight for this gear of 878 lb. 

Sessions Type K 
Gears No. 9, 10, 11 and 12 

This is the well-known Sessions gear as 
manufactured by the Standard Coupler 
Company and as used on 50,000 of the 
United States Railroad Administration 
cars. The bellmouth friction box is of 
drop forged steel, the friction blocks being 
of cast iron. The spring barrel is a section 
of steel tubing. The gear has a nominal 
travel of 2-1/16 in., the first % of which 
is spring travel and the remainder friction 
travel. The gear is put into the car under 
approximately % in. initial spring com- 
pression, but no friction compression, the 
friction elements being loose when the gear 
is first applied. This gear has a friction 
spring value of approximately 23,000 lb. 
No separate release springs are used. 

Each gear consists of eight parts, four 
of which are subject to wear. Wear of the 
parts cannot be taken up except by re- 
newal of parts. The gear is not self- 
contained but will fall apart when removed 
from the car. But little fitting or grinding 
is done in the manufacture of this gear 
and it is usually shipped loose, to be as- 
sembled in the car. The friction area of 
the gear increases as it is compressed and 
the solid blow is delivered upon the same 
metal that receives the friction load. 



10 



Draft Gear Tests of the U. 5. Railroad Administration 



The normal length of this gear is 20y 8 
in., requiring two 2*4 in. followers with 
each gear. The average weight of one gear 
is 252 lb., or 504 lb. per car, to which must 



friction springs, having a combined value 
of 30,000 lb. These springs are gradu- 
ated, the inner coils being shorter than the 
outer coils. 




Fig. 4— Sessions Type K Gear 



be added for comparative purposes, four 
followers per car, weighing 71 lb. each, 
giving a per car weight for this gear of 
788 lb. 

Sessions Jumbo 

Gears No. 13, 14 and 15 

This is a heavier gear, and of 3 in. nomi- 
nal travel, recently developed by the 
Standard Coupler Company. In general, 
it follows the same principle of wedge 
blocks as the older Type K gear of this 
company, there being changes, however, 
in the angles of the wedge blocks. The 
gear also includes both followers, being 
24% in. nominal length. 

The friction box is of drop forged steel 
and the spring barrel of cast steel with a 
closed bottom. There are six double coil 



The friction box, spring barrel, spring 
plate and center friction block are held 
together as a self-contained unit by means 
of a rivet and key arrangement. The side 
friction blocks and the follower are loose, 
however, so that the gear is not entirely 
self-contained. 

Each gear has a total of 22 parts, five of 
which are subject to wear; three of these 
are the cast iron friction blocks, the other 
two being the drop forged friction box and 
the drop forged follower. The gear has 
but little fitting or grinding done on it. 
The solid blow is taken by the same metai 
that carries the friction load, and wear will 
slightly reduce the value of the gear to re- 
sist solid blows. The friction area of this 
gear increases slightly as the gear is com- 
pressed. 



Draft Gear Tests of the U. S. Railroad Administration 



11 



The free length of this gear is 24^4 i n -> 
hence the gear is put in the car under 
Yg in. initial compression, all of which is 
spring compression, the friction elements 
being loose when the gear is first applied 
to the car. Of the 3 in. gear travel, 
when new, the first 3/16 in. is spring 
travel, at which point the friction blocks 
first become tight. The remainder is fric- 
tion travel. The average weight of one 
of these gears is 433 lb. and as no extra 
followers are required the comparative per 
car weight is 866 lb. 

Cardwell Type G-25-A 
Gears No. 16, 17 and 18 

This is the regular pattern Cardwell 
gear of the Union Draft Gear Company, 
but with the parts slightly modified to give 



seven contained friction members of cast 
iron. The customary transverse spring ar- 
rangement is used, with malleable iron 
spring-seat nuts threaded on the ends of 
the spring rod. The free length of this 
gear is 25-11/16 in. as against a pocket 
length of 24% in., so that the gear as as- 
sembled in the car is under an initial fric- 
tion compression of 1-1/16 in. This 
means, in other words, that the gear can 
wear an amount equal to 1-1/16 in. 
coupler travel before actual lost motion in 
the gear occurs. Of course, the ultimate 
resistance of the gear as well as its ca- 
pacity will have been reduced, but it is pos- 
sible to recover this in a large measure by 
adjusting the exposed spring-seat nuts. 
There is in addition to this an initial spring 
compression of % in. so that each spring 




*s 








— ' 




** 








s 




( 








\ 




\ r 










-\ 




/ i 




/ 












\ 




^ 












■>» 




^ 






^ 





Fig. 5 — Sessions Jumbo Gear 



a nominal travel of 2^4 in- It is used on 
19,000 of the United States Railroad 
Administration cars. The gear is of the 
double end type, the two friction casings, 
sometimes termed "housings" or "follow- 
ers," being of malleable iron. There are 



can, in addition to the wear above noted, 
take a permanent set of 3/16 in. be- 
fore the friction elements become loose 
on the spring rod. The magnitude of the 
initial compression of this gear gives a 
high starting resistance and a stiff com- 



12 



Draft Gear Tests of the U. S. Railroad Administration 



pression curve at the beginning of the gear 
travel. 

The gear has no independent release 
springs and the friction springs have a 
value of approximately 29,900 lb. When a 
solid blow comes on this gear some addi- 
tional metal is presented to receive it. 



Card well Type G-18-A 
Gears No. 19, 20 and 21 

This is the regular Cardwell gear of the 
Union Draft Gear Company, designed 
to fit in the standard 24% in. 
draft gear pocket and of 3-3/16 in. 
nominal travel. The remarks in general 




Fig. 6 — Cardwell Type G-25-A Gear 



The friction casings, which alone receive 
the solid blow, are castings with rather 
thin walls. There are a total of 20 parts 
per gear, nine of which are subject to 
wear. Seven of the wearing members are 
of cast iron and two are malleable iron, 
the latter being the main friction casings or 
followers. This gear is not self-con- 
tained but must be built up in the car. It is 
probably the most difficult of the gears to 
apply. All of the parts are rough with 
but little grinding or fitting done to them. 
The normal length of this gear is 24% 
in. and no followers are needed. The aver- 
age weight of one gear is 440 lb., giving 
a comparative per car weight of 880 lb. 



concerning the Cardwell Type G-25-A 
gear are applicable to this gear also. Each 
gear has a total of 20 parts, nine of which 
are subject to wear, seven of these being of 
cast iron and the other two being the main 
malleable iron heads or followers. 

The gear has a free length of 25 }4 in. as 
against a pocket length of 24% in. so that 
the gear, as assembled in the car is under 
an initial friction compression of % in., 
meaning that when wear equivalent to % 
in. coupler travel occurs the friction ele- 
ments become loose in the car. The springs 
are in addition under a combined initial 
compression of a % in., or 3/16 in. per 
spring. The value of the friction springs 
is approximately 29,900 lb. The nominal 



Draft Gear Tests of the U. 5. Railroad Administration 



13 



length of this gear is 24% in. and no fol- 
lowers are required. The average weight 
of one gear is 440 lh., giving a comparative 
per car weight of 880 lb. 

The relative performance of this gear 
and of the Cardwell G-25-A should be of 
interest inasmuch as the only difference 
in the two gears is in the length of the 
travel. All of the parts of both gears are 
the same except the two heads or follow- 
ers and these are designed in the case of 
the G-25-A gear to take up the first 7/16 
in. of travel as compared with the G-18-A 
gear, giving heavier initial compression 
but leaving the ultimate resistance prac- 



advantage of having the friction elements 
held in positive engagement during a 
longer period of wear. Whether or not 
high initial resistance prevents wear that 
may otherwise occur from the multitude 
of slight movements of the easier mov- 
ing gear may also be indicated by service 
tests of these two gears. 

Miner Type A-18-S 
Gears No. 22, 23 and 24 

This is a slightly modified arrangement 
of the well-known A- 18 gear of W. H. 
Miner and is the design as applied to 













! 










; % ■■■*'■■■■ ' ■ "■■'*- " -.•.■-.''••'■ _ - ;;;g 





Fig. 7— Miner Type A-18-S Gear 



tically the same for both gears. The G-25- 
A, therefore has a reduced travel but 
higher starting resistance. It may pos- 
sibly show a very slight loss in capacity 
due to this but on the other hand has the 



United States Railroad Administration lo- 
comotive tenders. The location of the fric- 
tion shoes has been changed as compared 
with the A- 18 gear. The present gear has 
a nominal travel of 2% in. 



14 



Draft Gear Tests of the U. S. Railroad Administration 



The barrel of the gear is of malleable 
iron and contains, by an interlocking ar- 
rangement, the two double coil friction 
springs and malleable iron spring plate or 
follower. The regular drop forged, hard- 
ened friction shoes, three in number, are 
used, with the central wedge of cast steel. 
The Miner rollers, three in number, and 
of 1 in. diameter tempered tool steel, are 
interposed between the central wedge and 
the friction shoes to allow greater friction 
pressures with possibly no greater tend- 
ency of the gear to stick. The entire fric- 
tion pressure is transmitted through these 
rollers. 

As applied to the car the main springs 
are under an initial compression of % in. 
and the preliminary spring of ^4 m « The 
function of this preliminary spring should 
not be confused with purely spring gear ac- 
tion, as the A-18-S gear starts off immedi- 
ately as a friction gear of high initial re- 
sistance. Inward movement of the fric- 
tion shoes is resisted first by the prelim- 
inary spring and subsequently by the main 
spring. Wear will increase the movement 
of the friction shoes upon the preliminary 
spring and decrease the movement upon the 
main springs. The travel of this 
gear should remain practically con- 
stant, irrespective of wear, and as wear 
occurs the friction shoes, which in the new 
gear extend }i in. outside of the friction 
barrel, will protrude farther because of the 
spreading action resulting from the pre- 
liminary spring. This will continue until 
wear equivalent to % in. coupler move- 
ment occurs when the friction shoes will 
extend 1% in. outside of the barrel and 
the shoes will then loosen. Up to this 
point however, the full travel of the gear 
will be realized as friction travel, although 
the capacity and ultimate resistance of the 
gear will be reduced. It should be pos- 
sible, however, to compensate for wear 
by inserting one or more ring washers be- 



tween the inner ends of the friction shoes 
and the spring cap or followers, thereby 
recovering the movement upon the main 
springs and restoring the original capacity. 

The gear has a main spring value of ap- 
proximately 42,000 lb. and in addition a 
preliminary spring value of approximately 
5,300 lb. It is held to the correct length 
and as a self-contained unit by means of a 
single % in. retaining bolt. The gear has 
a total of 18 parts, four of which are sub- 
ject to wear, one of these being the main 
barrel or cylinder. Wear on this part will 
reduce its ability to withstand solid blows. 
The friction area of this gear increases as 
the gear is compressed. The gear has con- 
siderable grinding and fitting done to it 
during its manufacture. 

The normal length is 22% in. so that 
two followers are required per car. The 
average weight of one gear is 346 lb., to 
which must be added for comparative pur- 
poses the weight of the two followers, 
giving a comparative per car weight of 
834 lb. 

Miner Type A-2-S 
Gears No. 25, 26 and 27 

This is a slightly modified arrangement 
of the A-2 gear of W. H. Miner, the nom- 
inal travel being 2]/ 2 in. The gear has the 
regular malleable iron cylinder with three 
hardened, drop forged friction shoes and a 
single cast steel central wedge, the cus- 
tomary rollers of the Miner design being 
interposed between the central wedge and 
the friction shoes. One double coil fric- 
tion spring is used. The rollers, three in 
number, are of tempered tool steel 1 in. in 
diameter by 3 in. long. The rollers in 
this gear, as in the A-18-S gear, are not 
directly cushioned by the springs, but re- 
ceive the entire friction pressure. 

The absolute free length of this gear is 
21 in., but it is held compressed to its 



Draft Gear Tests of the U. S. Railroad Administration 



15 



normal length of 20^ in. by the retain- 
ing bolt. The gear is thus under an in- 
itial friction compression of % in. Before 
this much wear could occur, however, or 
if wear equivalent to % in. of coupler 
movement should occur, the inner end of 
the central wedge would strike the spring 



that it is applied to the car as a single unit. 
This gear has a friction spring value of ap- 
proximately 22,800 lb. It is also fitted 
and bulldozed during the process of man- 
ufacture. The average weight of one of 
these gears is 207 lb. and there are re- 
quired two followers with each gear, weigh- 




Fig. 8— Miner Type A-2-S Gear 



cap, and the gear would then become 
purely a light capacity spring gear and 
further wear would be arrested. In this 
gear, as in the A-18-S, the total travel of 
the gear can never be reduced by wear, al- 
though the capacity and ultimate resistance 
will be decreased. The friction shoes will 
also extend farther out of the barrel as 
wear progresses. 

The gear has a total of 13 parts, four of 
which are subject to wear, one of these 
being the main barrel or cylinder. The 
friction area of this gear increases as the 
gear is compressed. The solid blow is 
taken upon the same metal that receives 
the friction load and wear will materially 
weaken the cylinder for taking care of the 
solid blow. The gear is self-contained so 
2 



ing 71 lb. each, giving a comparative per 
car weight of 698 lb. 

National Type H-l 
Gears No. 28, 29 and 30 

This is a new gear of 2*4 in. nominal 
travel, manufactured by the National Mal- 
leable Castings Company. A central fric- 
tion column with four ways in it is cast 
integral with the one follower of the gear. 
In these ways are four friction segments 
or shoes. The other, or movable follower, 
is arranged to wedge these shoes inwardly 
into the ways of the column and as the 
gear is closed the longitudinal movement 
of the shoes is resisted by a single coil 
friction spring that surrounds the friction 



16 



Draft Gear Tests of the U. S. Railroad Administration 



column below the wedges. Four inde- 
pendent corner posts of 1% in. diameter 
steel are provided to receive the solid blow 
so that this force is received on entirely 
different metal. An independent release 
spring surrounds each of these corner posts. 
The gear is held to any desired length and 
as a self-contained unit by means of two 
Y^. in. rods with castle nuts. 

All of the principal parts of this gear, 
including the friction members, are made 
of Naco Electric steel, the corner posts 
being of tempered knuckle pin steel. All 
of the friction members are hardened. The 
gear has a friction spring capacity of ap- 
proximately 29,200 lb. and an additional 
release spring capacity of approximately 
16,000 lb. The absolute free length of 
the gear is 24-25/32 in. so that it is put 
into the car under 5/32 in. initial com- 
pression, all of which is friction compres- 
sion. The gear can thus wear an amount 
equal to 5/32 in. travel or the spring take 
a set of 5/32 in. before the friction shoes 
become loose in the car. The capacity of 
the gear, however, will begin to depreciate 
as soon as any wear takes place. 

An interesting feature of this gear is 
that on release, the first action is a tendency 
to shift the friction shoes outward from 
their engagement with the center friction 
column, thus allowing greater pressures 
with possibly no greater tendency to stick. 
This is accomplished by having the bear- 
ing of the shoes upon the spring seat at 
a subtracting angle. Bronze pressure pads 
are provided for the contact spots on the 
spring seat and the outer head. These are 
not subject to wear, but to pressure only. 
The outstanding feature of this gear is that 
the friction elements are wedged inwardly, 
the outward reactions all being included in 
the box-shaped movable follower. There 
is no wear upon this member and wear 
should not noticeably affect the strength 



of the gear. Wear can be taken up by 
means of ring washers beneath the friction 
spring. 

The friction area . of this gear is con- 
stant, the pressure per square inch increas- 
ing as the gear is compressed, the entire 
bearing surface of the friction blocks 
sliding along the ways or flutes in the 
center column. This gear has a total of 
26 pieces, 5 of which are subject to wear, 
one of these being the main center column. 
Considerable grinding, fitting and working 
constitute a part of the manufacture of 
this gear and it may be termed a finished 
gear. 

The normal length is 24% in., so that 
no followers are required. The average 
weight is 428 lb. or a comparative per 
car weight of 856 lb. 

National Type M-l 
Gears No. 31, 32 and 33 

This gear is similar in construction to 
the National Type H-l, the most notice- 
able difference being that but two release 
springs are used instead of four as in the 
H-l gear. Otherwise the same description 
of parts, materials, and operation serves 
for both gears. The nominal gear travel 
is V/ 2 in. 

This gear has a friction spring value of 
16,700 lb. and an additional release spring 
value of 9,100 lb. The free length is 25% 
in. so that it is put into the car under y 2 
in. compression, the first 5/16 in. of which 
is spring compression, the remainder, 
3/16 in., being friction compression. Thus 
the gear can wear an amount equal to 3/16 
in. coupler travel before the friction shoes 
become loose in the car. There are a total 
of 26 pieces per gear, five of which are sub- 
ject to wear and one of these being the main 
center column. As in the H-l gear, the 
wearing surfaces are of hardened steel and 
are constant in area. 



Draft Gear Tests of the U. S. Railroad Administration 



17 



The normal length is 24% in., no fol- 
lowers being required. The average 
weight per gear is 372 lb. or a compara- 
tive per car weight of 744 lb. 

National Type M-4 
Gears No. 34, 35 and 36 - 
This gear is of the same general con- 
struction as the two preceding National 
gears but has three flutes in the center col- 



gear can wear an amount equal to 9/16 in. 
coupler travel before the friction shoes 
become loose. It is held to its normal 
compressed length of 24% in. by means of 
two % m - r °ds with castle nuts. The 
gear has a total of 17 pieces, five of which 
are subject to wear, one of these being 
the main center column. As in the other 
National gears, the wearing surfaces are 
of hardened steel and are constant in area. 










Fig. 9— National Type M-l Gear 



umn with three friction shoes, and has no 
independent release springs. Otherwise 
the general description is the same as 
heretofore given for the other National 
gears. The nominal travel is 2] 4 in. 

The gear has a spring value of 25,000 
lb. The absolute free length is 25-3/16 
in. so that it is put into the car under 
9/16 in. compression, all of which is fric- 
tion compression. This means that the 



The normal length is 24% in., no follow- 
ers being required. The average weight 
per gear is 322 lb. or a comparative per 
car weight of 644 lb. 

Murray Type H-25 
Gears No. 37, 38 and 39 
This gear is of the regular Murray pat- 
tern, without wear blocks, as manufac- 
tured by the Keyoke Railway Equipment 



18 



Draft Gear Tests of the U. S. Railroad Administration 



Company, but has been specially designed 
to give a nominal travel of 2% in. for use 
on 6,000 of the United States Railroad Ad- 
ministration cars. The followers, the side 
wedges and the cam blocks are of cast 
steel and are in general of sturdy design. 



the triple coil friction spring has a value 
of approximately 43,000 lb. These gears 
as included in the tests had no provision 
for taking up wear, but it is understood 
that a similar type is made with renew- 
able wear blocks. 




Fig. 10— Murray Type H-25 Gear 



This may be termed a double end gear, in- 
asmuch as there are friction elements in 
series at each end. 

The longitudinal movement of the heads 
or followers produces a corresponding in- 
ward movement of the side bars or wedges, 
this latter movement, through the four 
rollers and two cam blocks, producing an 
endwise compression of the friction spring. 
The rollers, which actually rotate during 
a compression of the gear, can never be 
loaded beyond the capacity of the spring, 
unless the spring should go solid before 
the limit of normal gear action is reached. 
No separate release springs are used and 



Each gear has a total of 13 parts, four 
of which are subject to wear, these being 
the four largest parts, viz., the cast steel 
end heads and the cast steel side bars. The 
friction area of this gear increases as the 
gear is compressed. 

The free length is 24-15/16 in. as against 
a pocket length of 24% in., so that the 
gear as assembled in the car is under an 
initial friction compression of 5/16 in. 
This means that the gear can wear an 
amount equal to 5/16 in. coupler travel 
before actual lost motion in the gear oc- 
curs. The ultimate resistance and the ca- 
pacity of the gear will, however, have been 



Draft Gear Tests of the U. S. Railroad Administration 



19 



reduced by such wear. In addition to this 
the spring is held under an initial com- 
pression of 11/16 in. The solid blow in 
this gear is taken by the same parts that 
receive the friction load and the bearing 
surfaces between the followers and the side 
wedges for the solid blows are not as ex- 
tensive as in some other gears. The gear 
is not self-contained and requires some 
special fitting up and manipulation to ap- 
ply it to the car, and some special ap- 
paratus is required to assemble the spring 
and rollers in their inter-locked positions 
between the side wedges. The parts of the 



Gould Type 175 

Gears No. 40, 41 and 42 
This gear of the Gould Coupler Com- 
pany has a cast steel barrel with a rectang- 
ular bellmouth for the cast steel friction 
wedges. These latter, two in number, are 
case hardened and are pressed outwardly 
against the friction faces of the barrel by 
a friction spring of leaf type, which is made 
up of two half-elliptic springs placed back 
to back between the wedges, each half 
being composed of eight plates, 3/16 in. 
by 7 in. by 8)4 in- lon g- This spring is 
applied under a slight initial compression 
but not enough to compensate for wear of 




Fig. 11— Gould Type 175 Gear 



gear as finished are rough with but little 
grinding or fitting. 

The normal length is 24% in. and no fol- 
lowers are required. The average weight 
of one gear is 376 lb., giving a compara- 
tive per car weight of 752 lb. 



any moment. The gear is supplied in ad- 
dition with a double coil release spring of 
38,000 lb. value. The gear is applied to 
the car without initial compression. It 
has a nominal travel of 2% in. 

There are a total of 22 parts to each of 



20 



Draft Gear Tests of the U. 5. Railroad Administration. 



these gears, four of the parts being subject 
to wear, one of these being the main cast 
steel barrel or housing. Wear can be 
readily taken up by the insertion of liners 
back of the friction wedges. The solid 
blow is delivered upon the same metal 



of the heads and the adjacent face of the 
rocker. Friction is obtained by one 
rocker sliding upon another and also by 
the rockers rotating in seats in the hous- 
ings. The gear has a nominal travel of 
2^2 in., but is put in the car under Y\ in. 





... ■■ ' " ■ 


- " 










'£■■•„ 








C^X^^lB 


pgpp 









Fig. 12 — Bradford Type K Gear 



that receives the friction load, and wear 
also tends to weaken the gear. The fric- 
tion area is constant. The gear is self- 
contained when new, but wear will shortly 
loosen the parts so that it will fall apart 
when removed from a car. 

The normal length is 22% in., requir- 
ing a 2% in. follower with each gear. The 
average weight of one gear is 337 lb., to 
which must be added for comparative pur- 
poses two followers per car, weighing 71 lb. 
each, giving a per car weight for this gear 
of 816 lb. 

Bradford Type K 

Gears No. 43, 44, 45, 46 and 47 

This gear is manufactured by the Brad- 
ford Draft Gear Company. It is of the 
rocker type, having malleable iron heads 
or spring housings at each end with two 
pairs of inter-engaging, rotative knuckles 
between the springs. The action is such 
that each spring is compressed between one 



initial spring compression. The friction 
elements are just tight when the gear is 
put into the standard pocket. 

There are a total of 10 pieces to each 
gear, six castings and four springs. It is 
noticeable that every piece of the gear, ex- 
cept possibly the springs, is subject to 
wear. Upon a strict analysis the rocker 
ends of the springs might even be in- 
cluded, as the rockers move across the end 
faces of the springs. The friction area is 
constant and where one rocker slides upon 
another there is practically line contact. 
The solid blow is taken by the same metal 
that receives the friction load. The gear 
is not self-contained but must be assem- 
bled in the car. The two friction springs 
are regular A. R. A. Class G springs, work- 
ing in series, and the spring value of the 
gear is accordingly 30,000 lb. The parts 
of the gear as furnished are rough. 

The normal length is 24% in. and no 
followers are required. The average 



Draft Gear Tests of the U. S. Railroad Administration 



21 



weight of one gear is 386 lb. or a compara- 
tive per car weight of 772 lb. 

Waugh Plate Type 

Gears No. 48, 49 and 50 

This is the well-known plate gear of the 
Waugh Draft Gear Company. As included 
in the tests each gear was made up of four 
sets of plates in series, each set consisting 
of 15 spring steel plates *4 hi. by 6 in. by 
11% in. Half oval followers of cast steel 
are supplied at each end, and two sep- 
arators and one full oval complete the 
gear proper. In addition, however, two 
guide plates or wear plates, are supplied 



a total of 65 parts, or 67 parts including 
the wear plates. 

In this gear it is difficult to give a rela- 
tive per car weight because of the differ- 
ence in yoke dimensions required. Each 
gear weighs 420 lb. without the two wear 
plates, which latter will weigh about 30 lb. 
each. Yoke spacers should then be added, 
so that a comparative per car weight of 
960 lb. has been allowed for this gear. 

Christy 

Gears No. 51, 52 and 53 

This gear is under development by the 
American Car Roof Company. It had not, 




Fig. 13 — Waugh Plate Gear 



for each gear, these being bolted or riveted 
to the draft sills to fill out the 12% in. 
sill spacing and to hold the parts of the 
gear in alignment. 

The nominal length is 24% in. and the 
nominal travel 2^4 m - The gear has a 
friction area of great extent and it is hardly 
probable that wear would ever materially 
reduce the travel or capacity. If the 
spring plates should take any permanent 
set, however, the travel and capacity of the 
gear would be decreased. Every gear has 



up to the time of the beginning of the tests, 
been developed to a commercial stage and 
has been included in these tests only upon 
the request of the mechanical department 
of one of the railroads. The gear, which 
has a nominal travel of 2 J / 2 in., follows 
in general the better-known Sessions prin- 
ciple of wedge blocks, except that the cen- 
ter block is made in halves with a roller 
between them to form a fulcrum. Wear is 
to be compensated for by using a roller of 
a larger size. 



22 



Draft Gear Tests of the U. S. Railroad Administration 



The outstanding feature, and the point 
wherein it differs from all other gears in 
the test, is that the frictional resistance of 
the gear is compounded. In most draft 
gears the friction movement is obtained, 
and to a greater or less degree the fric- 
tional resistance is controlled by the direct 



2y 2 in. less length than the outer coil. 
The friction spring has a total value of 
27,000 lb. No separate release springs 
are used. The friction box and spring 
barrel are in one piece, of cast steel, with 
a removable head bolted on the spring 
end of the barrel. All of the parts of this 




m 



a 



J u 



it X )' )/ / 

K"""N' '/"~~\i fr"*"~*v y^^irt — si 

!)' f / ( ) ( lif ! / 



y- — •? 
\\ 

.J) 



o 



Fig. 14 — Christy Gear 



compression of springs. In this gear the 
outer, or main friction members, are re- 
sisted, not by the spring directly but by 
other friction members, and these latter are 
then resisted by the spring itself, the fric- 
tional resistance being thus multiplied. 
This should result in a gear of very high 
resistance but may also result in uncertain 
and uncontrolled resistance. 

The frictional resistance of the gear is 
thus compounded by having the inward 
movement of the halves of the center wedge 
block seat upon and expand the additional 
pair of friction shoes which press upon 
the inner faces of the spring portion of the 
barrel. These last named friction shoes 
rest upon and compress the friction spring 
which is graduated, the inner coil being of 



gear are exceedingly heavy, the walls of 
the spring barrel, for example, being of 
1 in. stock. The gear has a total of 28 
parts, 8 of which are subject to wear, 
among these being the main cast steel bar- 
rel or housing. The gear is not self-con- 
tained but the friction members can fall 
out when the gear is removed from the 
car. The solid blow is taken upon the 
same metal that receives the friction load 
and wear will reduce the strength and 
value of the gear to resist solid blows. 
The friction area is practically constant, 
although some new surfaces are constantly 
coming into bearing and others going out 
of bearing as the gear is compressed. 

The absolute free length is 22-7/16 in. 
as against a pocket length of 22% in., so 



Draft Gear Tests of the U. S. Railroad Administration 



23 



that the gear in the car is under but 1/16 
in. initial compression. Upon very slight 
wear, therefore, or set of the springs, the 
friction members will be loose. The aver- 
age weight of one of these gears is 442 lb. 
and having a nominal length of 22% 
in. there must be added to this the weight 
of two followers per car, giving a compar- 
ative weight of 1026 lb. per car. 

Harvey Friction Springs 
Gears No. 54, 55 and 56 

These are the regular interwound Harvey 
friction springs as manufactured by 
the Frost Railway Supply Company. 
Each gear, as included in the tests, 
consisted of two of these springs 
set in twin fashion, side by side. 
The free height of each interwound 
spring group is 8 in., and so wound as to 
allow 2 in. of movement from this height, 
thus having a nominal travel in the car of 
1% in. Each group has a plain centering 




Fig. 15 — Harvey Friction Springs 

coil of % in. diameter bar wound on a 
2% in. diameter mandrel and of 7% in- 
free height. In receiving the solid blow 
the main, or inner, of the two specially 
shaped friction coils goes solid. This bar 



is made with flattened contact faces to re- 
ceive the solid blow. 

This type of gear will not work in the 
standard pocket without special housings. 
The average weight of a group of these 
springs is 52 lb. or 208 lb. per car. It is 
difficult to give a comparative per car 
weight but in order to compare the ar- 
rangement with the other gears of the test 
there has been added eight followers, each 
9 in. by 12 in. by iy 2 in., weighing 45 lb. 
each, two yoke abutments, weighing 40 lb. 
each, and four rivets for the yoke abut- 
ments, weighing 5y 2 lb. each, giving a 
comparative per car weight of 670 lb. 

A. R. A. Class G Springs 
Gears No. 57, 58 and 59 

Regular A. R. A. Class G draft springs 
drawn from ordinary railroad stock have 
been included in the tests. Each gear as 
numbered above was composed of two 
complete inner and outer coil springs, 
tested in twin fashion. 

The details of each spring group are as 
follows: 

Outer Coil 

1-9/16 in. diameter bar. 
8 in. outside diameter coil. 
7% in. free height. 
5^4 m - solid height. 

Inner Coil 

1 in. diameter. 

4% in. outside diameter coil. 

7y 2 in. free height. 

5^4 in. solid height. 
Each group has thus a possible deflection 
of 2% in. at a load of 30,360 lb. or a de- 
flection of 2% in. per gear at a load of 
60,720 lb. The average weight of a group 
is 55 lb. or 110 lb. per gear. To this is 
added for comparative purposes the same 
parts as for the Harvey springs, giving a 
comparative per car weight of 682 lb. 



SELECTION AND CONDITION OF TEST GEARS 



At the beginning of these tests the vari- 
ous manufacturers were asked to furnish 
gears for test purposes, so that the gears 
as tested were in each instance procured 
directly from the proprietor, with full 
knowledge on his part that they were for 
test purposes. Whether or not gears of 
average manufacture were furnished must 
be decided from previous or additional ex- 
perience with the several gears and from 
a knowledge of the manufacturing practices 
of the concerns. Unless a definite state- 
ment to the contrary appears in this re- 
port it is to be understood that gear con- 
ditions and performances as developed dur- 
ing the tests are in accordance with what 
is believed to be average conditions. 

Immediately upon receipt of a test gear 
it was given a test number and then taken 
apart. The parts were marked, and meas- 
ured for comparison with the manufactur- 
er's drawings and for later comparative 
tests measurements. The gears were reas- 
sembled with the parts in their original 
positions and were given a definite amount 
of preliminary drop test work to condi- 
tion them for the regular tests. 

Westinghouse D-3 

Gears No. 1, 2 and 3 

These gears as received were in good 
average condition and conformed very 
closely to the dimensions as given on the 
manufacturer's drawings. The gears had 
not been built up of maximum dimension 
parts to produce unusual capacity. The 
customary practice of machining and 
grinding certain parts had been followed 
and the gears had been worked in the bull- 
dozer as is the regular practice in their 



manufacture. They showed also slight in- 
dication of drop test work but not an ex- 
cessive amount. The results obtained in 
the tests agree very well with results ob- 
tained in other tests of the same gear, par- 
ticularly in routine acceptance tests of 
gears for United States Railroad Adminis- 
tration cars. 

Westinghouse NA-1 
Gears No. 4, 5, 6, 7 and 8 

These gears do not have as much ma- 
chine work done on them as in the case 
with the Westinghouse D-3 gear, but are 
carefully fitted and assembled. The gears 
as received appeared to be in average con- 
dition and for the rougher character of the 
work, agreed very closely with the draw- 
ings. The gears had been bulldozed and 
had undoubtedly been under the drop test- 
ing machine. The bulldozing, it is under- 
stood, is a regular process in their manu- 
facture and the drop test work had not 
been extensive. The gear parts were not 
over size and the results of the tests in gen- 
eral are believed to be representative of 
the action of the average product. 

Sessions K 
Gears No. 9, 10, 11 and 12 

These gears are furnished commercially 
with but little finishing, it being the man- 
ufacturer's practice to gage the parts and 
grind the friction blocks when necessary to 
bring them to gage or to smooth up the 
bearing surfaces. The gears as received 
represented average workmanship and 
conditions and showed evidence of having 
been under the drop machine for a few 
movements. The results of the tests in 
general are comparable with previous tests 



24 



Draft Gear Tests of the U. S. Railroad Administration 25 



of the same gear, particularly in routine 
acceptance tests of gears for United States 
Railroad Administration cars. 

Sessions Jumbo 
Gears No. 13, 14 and 15 

These gears as received represented av- 
erage workmanship and condition. They 
showed slight evidence of having been un- 
der the drop test machine for a few move- 
ments at some previous time, although the 
friction surfaces had a light coating of rust 
on them when received. The results of the 
tests are believed to be representative of 
the commercial gear. 

Cardwell G-25-A 

Gears No. 16, 17 and 18 

These gears as received were in average 
condition as to workmanship and showed 
indications of having been under the drop 
machine. The springs furnished with the 
test gears were of excessive length, the av- 
erage free length being 10-1/16 in., where- 
as the drawing dimension is but 9*4 i n » 
With all the parts properly assembled on 
the spring rod, the springs from the draw- 
ings should be under 3/16 in. compression 
while with the gears as finished the springs 
were under % in. compression. When as- 
sembling the gears in the frame for testing, 
with a pocket of the same length as in the 
car, it required the extreme efforts of two 
men working on an eight-foot wrench to 
screw up the spring nuts. It is noted also 
that the average drop test results obtained 
from these gears are greater by slightly 
more than 4 in. than the average results 
obtained in routine acceptance tests of the 
same gears for United States Railroad Ad- 
ministration cars, whereas with all other 
gears used on United States Railroad Ad- 
ministration cars the average of the test 
gears was lower than the average of the 
commercial gears. The lowest capacity 
gear of this type in the present tests was 
more than 3 in. greater than the highest 



capacity gear of the same type found in the 
United States Railroad Administration ac- 
ceptance tests. It is therefore believed that 
the results obtained for these test gears are 
not representative of what may be expected 
from the regular product as furnished com- 
mercially. 

Cardwell G-18-A 
Gears No. 19, 20 and 21 

These gears were received in average con- 
dition as to workmanship, and the parts 
conformed more closely to the drawings 
than in the case of gears number 16, 17 and 
18, although they averaged above the 
drawings. The individual variations, 
however, would probably be accepted as 
within manufacturing limits. The averages 
are believed to more nearly represent the 
true value of the commercial gear than 
those obtained from test gears number 16, 
17 and 18. These gears were submitted 
near the close of the test program. 

Miner A-18-S 
Gears No. 22, 23 and 24 

These gears as received were in good 
average condition as to workmanship and 
material and the parts conformed closely 
to the dimensions as given on the draw- 
ings. They showed evidence of having 
been given some slight work, at least in the 
bulldozer, this being a part of the regular 
process of manufacture. The results ob- 
tained in these tests are in harmony with 
those of other tests and the gears as tested 
are believed to be representative of the 
commercial product. 

Miner A-2-S 
Gears No. 25, 26 and 27 

The condition of these gears as received 
corresponds with that of the Miner A-18-S 
and the test gears are believed to be repre- 
sentative of the commercial gears of this 
type. 



26 



Draft Gear Tests of the U. S. Railroad Administration 



National H-l 

Gears No. 28, 29 and 30 

These gears as received conformed 
closely to the drawings' dimensions, and 
the results obtained are comparable with 
results obtained in other tests of this gear. 
They showed evidence of having been 
worked under a drop machine or in a bull- 
dozer, the latter being a regular operation 
in the manufacture of the gear. The re- 
sults of the test are believed to be repre- 
sentative of the gears as furnished com- 
mercially. 

National M-l 

Gears No. 31, 32 and 33 

These gears as received were in the 
same general condition as those of the Na- 
tional H-l type and the results, which con- 
form to results of other tests, are believed 
to be representive of the commercial prod- 
uct. 

National M-4 
Gears No. 34, 35 and 36 

The condition of these gears as received 
corresponds with that of the other Na- 
tional gears and is believed to be repre- 
sentative of the commercial product. 

National M-4 
Gears No. 34, 35 and 36 

The condition of these gears as received 
corresponds with that of the other National 
gears and is believed to be representative 
of the commercial product. These gears 
were submitted near the close of the test 
program. 

Murray H-25 

Gears No. 37, 38 and 39 

These gears as received were in average 
condition except that they had been given 
considerable work under the drop machine. 



In one case the friction surfaces were badly 
galled and scored. While the Murray gear 
is furnished commercially of rough cast- 
ings and while these test gears had prob- 
ably been given more conditioning than 
any other gears in the test, yet the results 
are not believed to have been influenced 
by it, especially as they are just slightly 
below the average of routine acceptance 
tests of the same type of gears for United 
States Railroad Administration cars. 

Gould 175 

Gears No. 40, 41 and 42 

These gears as received conformed 
closely to the manufacturer's drawings and 
appeared to be in good average condition 
except that a coating of grease was found 
in the interior of the gears, upon the top 
surfaces of the wrought steel follower 
plates that rest upon the main coil springs. 
The bottom ends of the friction wedges, as 
well as the lower ends of the leaf springs, 
bear upon the top surface of this plate and 
have a lateral motion thereupon. The 
main friction surfaces were free from 
grease. This condition was reported to the 
manufacturers, who disclaimed all knowl- 
edge of the presence of the grease, and at 
their direction the parts were cleaned and 
the gears placed in a condition satisfactory 
to their representative, who inspected them 
upon invitation. These test gears had been 
given some slight preliminary work but 
not immediately before shipment, as one 
of the gears had a light deposit of rust 
upon the friction surfaces. The results of 
the tests are believed to be representative 
of the action of the commercial product. 

Bradford K 

Gears No. 43, 44, 45, 46 and 47 

The undeveloped state of this gear makes 
it impossible to compare the test gears 



Draft Gear Tests of the U. S. Railroad Administration 



27 



with the commercial product. The hous- 
ings showed porosity and contained numer- 
ous small checks. A. R. A. Class F springs 
were sent in mistake for the Class G 
springs called for in the drawings. The 
gears were accordingly set up with Class 
G springs drawn from regular railroad 
stock. Several variations from the draw- 
ings were found. These gears are to be 
furnished commercially of rough castings, 
without any bulldozing or other working, 
and the test gears as received were in this 
condition, never having been operated be- 
fore shipment. 

Altogether, the test results from these 
gears are not satisfactory. It is felt that 
avoidable defects in workmanship and de- 
sign are responsible, at least in part, for 
the breakage of gear parts that will be 
noted as the report proceeds. 

Christy 
Gears No. 51, 52 and 53 

This is an undeveloped gear which has 
never been furnished commercially, so 
that comparisons are impossible. It is un- 
derstood that the gears are designed to be 
furnished regularly of rough castings. The 
test gears, however, had all of the friction 
surfaces machined and almost the entire 
external surface of the barrel had been 
shaped off to give true surfaces and correct 
dimensions. The springs averaged % in. 
less in length than called for on the draw- 
ings and the gears themselves averaged ap- 
proximately % in. less in length than the 
drawing dimensions, so that % in. of free 
slack would have been present in each car 
with these new gears applied. The gears 
also had % in. less of travel per gear than 
called for on the drawings. The drawing 



dimensions for the roller for the center 
wedge block are 1 in. in diameter by 6% 
in. long. In the three gears as received, 
the rollers were found to be of the follow- 
ing diameters: 

Gear No. 51 — % in. diameter. 
Gear No. 52 — 1| in. diameter. 
Gear No. 53 — 1 T V in. and 1% in. 
diameter (tapered). 

This finding at once raises the question 
as to whether in repairs the correct size of 
roller would be used and whether, in fact, 
it would not be frequently omitted en- 
tirely. The condition of the gears of this 
type indicated that this company was not 
in a position to furnish commercial gears. 

Harvey Friction Springs 
8 in. x 8 IN. 

Gears No. 54, 55 and 56 

The spring groups constituting these 
gears conformed reasonably close to the 
drawing dimensions except for the plain, 
inner coil centering springs which averaged 
7Jf in. in free height instead of 7% in. 
as shown on the drawings. The results of 
the tests are believed to be representative 
of the commercial product. 

A. R. A. Class G Springs 

Gears No. 57, 58 and 59 

The G springs used for the test were of 
ordinary carbon steel, oil tempered, drawn 
from regular railroad stock. The follow- 
ing tabulation will give the comparison of 
the test springs with the specification re- 
quirements of the American Railroad Asso- 
ciation: 



28 



Draft Gear Tests of the U. S. Railroad Administration 





Outer Coil Spring 


Inner Coil Spring 


Free 
Height 


Outside 
Diameter 


Diameter 
of Bar 


Free 
Height 


Outside 
Diameter 


Diameter 
of Bar 




7M in. 


7tt in. 


Ihi in. 


111 in. 


4% in. | §4 in. 




Specified Dimension 


7% in. 


8 in. 


1& in. 


7% in. 


4% in. 


lin. 





9,000 LB. DROP TESTS 



After measuring the test gears and reas- 
sembling them with their parts in their 
original positions, the 9,000 lb. drop tests 
were made. Except for a few gears that 
were added at a later date, the original se- 
ries of drop tests was made at the Mt. Clare 
shops of the Baltimore & Ohio Railroad. 
After the car-impact tests at Rochester, the 
same gears were submitted to a second se- 
ries of drop tests under the Pennsylvania 
Railroad machine at Altoona for check 
purposes, at which place the last few gears 
also were given their original drop tests. 

The drop tests were in all instances made 
with the gears supported upon a solid an- 
vil, a heavy plate casting being inserted 
instead of the springs regularly used be- 
neath the anvil of the Baltimore & Ohio 
machine. Before beginning the drop tests 
of either of the above series each gear was 
given a certain amount of preliminary 
work to insure the proper seating of the 
parts. The uniform practice was followed 
of first determining the drop test value of 
each gear, by dropping the weight from 1 
in. free fall and then increasing the fall 
by 1 in. increments, until the closing point 
was reached. The gear was then given 10 
blows from 1 in. below the solid height, 
which usually resulted in building up the 
capacity of the gear slightly. After this 
preliminary work the regular drop tests 
were made, the tup being again dropped 
through heights increasing by 1 in. incre- 
ments until the closing point was reached, 
as evidenced by flattening or shearing of 
lead records. In the case of gears such as 
the Harvey springs the solid point was pre- 
viously determined from a preliminary 
static test and this point worked to in the 
drop test. 



Two drop test diagrams have been re- 
produced for each type of gear to show 
the amount of gear closure at successive 
drops. These are shown in Figs. 18 to 35 
inclusive, at the end of the chapter on 
static tests, along with the static diagrams 
for the same gears. The information for 
plotting the drop test diagrams was ob- 
tained during the first series of drop tests 
by causing the tup to drive a nail into the 
end of a wooden post, the penetration of 
the nail denoting gear closure for each suc- 
cessive drop. The diagrams have been 
plotted to the exact points recorded, with 
no averaging or smoothing up of the 
curves. The regularity of gear action can 
thus be seen and in such a test this is of as 
much, if not more interest than the general 
trend of the line. 

Some of the drop test figures obtained in 
these tests are higher than usually reported 
for gears of the same type. The care taken 
to have all surfaces in goo'd condition and 
the uniformity of testing conditions in- 
sures that the present results are compar- 
able with each other. In general through- 
out this report the drop tests are reported 
in terms of "total fall," this being the free 
fall plus the penetration or actual travel 
of the gear. Some confusion has existed 
heretofore in this respect but it is proper 
to express these results in total fall rather 
than free fall if the true drop test capaci- 
ties are to be compared. 

The recoil of the 9,000 lb. weight was 
also measured by means of a special slide 
on the side of the drop machine. The 
quantities as tabulated are for the total re- 
coil of the weight above the lowest point 
reached by it in closing the gear. The 
drop test capacity, foot pounds of work 



— 29 — 



30 



Draft Gear Tests of the U. S. Railroad Administration 



done, is accordingly represented by the 
potential energy in the weight at a height 
corresponding to the total fall required 
to close the gear. The energy given out 
by the gear upon release is denoted by the 
amount of recoil of the weight. The work 
absorbed is found by subtracting the en- 
ergy of recoil from the "work done," or 
the total energy required to close the gear. 
A discussion of the individual perform- 
ance of the gears in the drop test follows: 

Westinghouse D-3 

Gears No. 1, 2 and 3 

The action of these gears under the drop 
was entirely satisfactory. The initial flat- 
ness of the curves shows the result of the 
preliminary spring action and the curves 
as a whole indicate that the gear action is 
reasonably consistent throughout the en- 
tire range. The average total fall of the 
9,000 lb. tup required to close a new gear 
of this type, when in good condition, is 
taken at 19.8 in., and the total recoil of 
the weight at 3.8 in. These figures are ar- 
rived at by averaging all of the drop test 
results for these gears, the same practice 
having been followed for each gear unless 
a statement to the contrary appears. 

Westinghouse NA-1 

Gears No. 4, 5, 6, 7 and 8 

The drop test results on these gears are 
not quite so regular as on the older West- 
inghouse D-3 gear, but while the diagrams 
are more irregular, the action in general is 
good. The results also are considerably 
higher, hence it cannot be expected to find 
as regular action as in the lighter gear. 
Gear No. 8 showed slightly less in capacity 
than any of the others of this type. No 
breakage or failure of any kind occurred 
during these drop tests. The average total 
fall required to close a new gear of this 
type, when in good condition, is taken as 



26.0 in., this being the average value of 
the three gears taken through the test. The 
total recoil is taken at 3.4 in. 

Sessions K 
Gears No. 9, 10, 11 and 12 

The drop test diagrams for these gears, 
while not so smooth, are yet good for a 
gear of such short travel. In gears No. 9 
and No. 10 the spring barrels began to 
scale before the gears went solid; in the 
case of gear No. 9 this began at 13 in. free 
fall, and in the case of gear No. 10 at 12 
in. free fall. Failure of the gears had 
therefore begun before closure and hence 
the tests are not satisfactory. The average 
total fall required to close a new gear of 
this type, when in good condition, is 
taken as 18.8 in., this being the average 
value of the three gears taken through the 
test, and the total recoil at 4.3 in. 

Sessions Jumbo 
Gears No. 13, 14 and 15 

This gear showed considerably more ca- 
pacity and at the same time more uniform 
action under the drop test than the previous 
Sessions K gear. The spring barrel of gear 
No. 13 developed a crack during this test. 
The average total fall required to close a 
new gear of this type, in good condition, 
is taken at 28.1 in. and the total recoil at 
5.2 in. 

Cardwell G-25-A 
Gears No. 16, 17 and 18 

The action of these gears under the drop 
was good, the diagrams being especially 
smooth and regular. The cast iron friction 
blocks formed decided depressions in the 
malleable iron heads, however, and a crack 
developed at one corner of one of the fric- 
tion blocks, while in the final drop tests at 
Altoona one of the side friction members 



Draft Gear Tests of the U. S. Railroad Administration 



31 



was broken in halves. The average drop 
for the test gears of this type is 21.1 in., 
but as heretofore explained, it is believed 
that these test gears are not representa- 
tive, the average drop test results obtained 
in United States Railroad Administration 
acceptance tests being 16.6 in. The gear is 
therefore credited with a value midway be- 
] tween these figures, or 18.9 in. total fall 
required to close an average new gear when 
in good condition. The average total re- 
coil to be expected is taken at 2.8 in. 

Card well G-18-A 

Gears No. 19, 20 and 21 

This gear showed smooth and regular ac- 
tion under the drop, and the diagrams are 
entirely satisfactory. The springs of gear 
No. 20 took a slight set during the drop 
tests. The average total fall required to 
close a new gear of this type, in good con- 
dition, is taken at 19.6 in. and the total 
recoil at 1.5 in. 

It is interesting to note that whereas 
from the mechanics of the two types of 
Cardwell gear, the G-18-A should be of 
higher capacity than the G-25-A, yet the 
average results obtained from the test gears 
show 1.5 in. more fall required for the 
G-25-A than for the G-18-A. This shows 
further warrant for the action taken in al- 
lowing a reduced drop test value for the 
G-25-A gear. 

Miner A-18-S 

Gears No. 22, 23 and 24 

The drop tests of these gears were satis- 
factory and the diagrams denote especially 
uniform gear action for all ranges. This 
is particularly noticeable because of the 
fact that the gear has a travel of but 2% 
in. The average total fall required to close 
'a new gear of this type, in good condition, 
is taken at 19.9 in. and the total recoil at 
4.6 in. 



Miner A-2-S 

Gears No. 25, 26 and 27 

These gears did not show so regular 
under the drop as the previous Miner gears 
but the diagrams are good. The drop ca- 
pacity, however, is low, the average total 
fall required to close a new gear of this 
type, in good condition, being 13.2 in. 
The total recoil is taken at 3.8 in. In 
gear No. 25 the main spring went solid 
during this test. 

National H-l 

Gears No. 28, 29 and 30 

This gear developed an unusually high 
capacity under the drop and while the dia- 
grams are not entirely smooth, yet, con- 
sidering the amount of fall and the short 
travel of 2y 2 in., the gear action is good. 
The average total fall required to close a 
new gear of this type, in good condition, 
is taken at 31.2 in., and the total recoil 
at 4.6 in. 

National M-l 

Gears No. 31, 32 and 33 

The drop tests of these gears did not 
produce diagrams proportionally as 
smooth as those of the previous National 
gears, considering their lower capacity. 
The diagrams, however, show reasonably 
uniform gear action. The average total 
fall required to close a new gear of this 
type, in good condition, is taken at 19.2 in., 
and the total recoil at 3.4 in. 

National M-4 

Gears No. 34, 35 and 36 

The action of this gear under the drop 
was very similar to that of the National 
M-l just described. The average total fall 
required to close a new gear of this type, 
in good condition, is taken at 21.5 in., 
and the total recoil at 2.4 in. 



32 



Draft Gear Tests of the U. S. Railroad Administration 



Murray H-25 

Gears No. 37, 38 and 39 

These gears, while not of high capacity, 
showed the most regular action of any fric- 
tion gear tested. The diagrams are un- 
usually smooth and indicate consistent ac- 
tion throughout the full range of the gear. 
Considerable chafing and wear occurred 
during the closures under the drop. Upon 
removing one of the heads a cloud of dust 
could be blown from the friction sur- 
faces. Unquestionably, this wear would 
soon deteriorate the gear. The average 
total fall required to close a new gear of 
this type, in good condition, is taken at 
17 in., and the recoil at 3.3 in. 

Gould 175 

Gears No. 40, 41 and 42 

These gears showed good action under 
the drop except for the fact that in each 
instance the plates of the friction spring 
took a slight permanent set. The gears 
showed high recoil and because of this 
feature it was difficult to keep them in posi- 
tion on the anvil. The average total fall 
required to close a new gear of this type, 
in good condition, is taken at 18.1 in. and 
the total recoil at 7.1 in. 

Bradford K 

Gears No. 43, 44, 45, 46 and 47 

The drop testing of these gears was diffi- 
cult and unsatisfactory. The springs went 
solid before the heads of the gears came 
together and gears No. 43 and No. 44 
failed by splitting the heads. The fail- 
ures were undoubtedly due to this spring 
condition, as extremely high forces are set 
up in this, as in most friction gears, if the 
springs go solid before the gear is closed. 
Gear No. 45 also developed a cracked head 
during the drop test. It is noticeable that 
the portion of the head immediately back 



of the coupler butt, in buffing, is not prop- 
erly supported. Another serious point is 
that in several instances the heads pinched 
and stuck in the frame on release. These 
gears showed low capacity and high recoil 
under the drop, their action being very 
little different from that of a spring gear. 
The average total fall required to close a 
new gear of this type, in good condition, 
is taken at 10.8 in. and the total recoil at 
5.3 in. 

Waugh Plate Type 

Gears No 48, 49 and 50 

These gears gave reasonably smooth dia- 
grams in the drop test but in each instance 
the plates took a permanent set. The drop 
capacity is low and the recoil high. The 
gear is of especially easy movement at the 
beginning of its travel. The average total 
fall required to close a new gear of this 
type, in good condition, is taken at 13.9 in. 
and the total recoil at 7.6 in. 

Christy 
Gears No. 51, 52 and 53 

This gear was very erratic under the 
drop, and the action is not at all satis- 
factory. The gears as tested were shorter 
than the pocket dimension and this clear- 
ance allowed the wedge roller to get out 
of position upon recoil. The total fall re- 
quired to close the test gears ranges from 
14.3 in. to 26.3 in. It is therefore difficult 
to set an average value, but in the absence 
of better uniformity the three results have 
been averaged and the total fall set at 19.6 
in. for this gear. The total recoil is taken 
at 5.1 in. 

Harvey 8 in. x 8 in. Springs 

Gears No. 54, 55 and 56 

Each of these gears as tested consisted of 
two Harvey 8 in. x 8 in. springs, set side 



Draft Gear Tests of the U. S. Railroad Administration 



33 



by side upon the anvil. The gears showed 
but little capacity under the drop, although 
the action was regular. In the case of gear 
No. 55 the springs took a slight permanent 
set. A total fall of 9.5 in. has been set as 
the drop test value of this gear (two com- 
plete springs) and the total recoil is taken 
at 4.2 in. 

A. R. A. Class G Springs 
Gears No. 57, 58 and 59 

Each of these gears as tested consisted of 
two A.R.A. Class G springs, set side by 
side upon the anvil. The springs showed 
low capacity in the drop test, but the action 
was smooth throughout the range of the 
springs. A total fall of 5.8 in. has been 
set as the drop test value of two Class G 
springs, working either in twin or tandem 
fashion, and the total recoil is taken as 
4.1 in. 

Summary of 9,000 Lb. Drop Tests 

The table, Fig. 16, has been prepared to 
show a summary of the drop tests, and the 
following paragraphs will explain the sev- 
eral columns of this table: 

Column 1 is selfrexplanatory. 

Column 2 gives the nominal travel as 
called for on the manufacturer's drawings. 

Column 3 identifies the test gears by 
number. 

Column 4 gives the actual travel ob- 
tained from the gears in the drop tests. In 



cases where the free length of the gear is 
less than the standard pocket dimension 
the actual travel has been given and an ex- 
planatory note made in Column 14. 

Column 5 gives the actual free fall of 
the 9,000 lb. weight required to just close 
the new test gears. These figures do not 
include the travel of the gear. 

Column 6 gives the actual total fall re- 
quired to just close the new test gears and 
is obtained by adding the quantity in Col- 
umn 5 to the actual travel as given in 
Column 4. 

Column 7 gives the actual recoil of the 
9,000 lb. weight from the fall indicated in 
Column 6. The recoil is from the lowest 
point reached by the weight when the gear 
was just closed. 

Column 8 indicates the work done by the 
9,000 lb. weight falling through the 
heights given in Column 6. 

Column 9 represents the energy ab- 
sorbed by the gear, based on the work done 
as given in Column 8, less the energy of 
recoil (Column 7). 

Columns 5 to 9 give the individual re- 
sults actually obtained with the test gears. 

Columns 10 to 13 give average or modi- 
fied results of a similar character, such as 
may be expected from gears of the same 
type, as they are manufactured and fur- 
nished commercially, with no selection for 
test purposes. 



34 



Draft Gear Tests of the U. S. Railroad Administration 



1 

8: 


® 










CO 








si 


k 

1 




© 




1 


Ss 
1 


15 


15 
1 


(5 
5 


is 






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P 
k) 


55 


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STATIC TESTS 



Immediately upon the completion of the 
drop tests the same two gears of each type 
were closed in a testing machine at a speed 
of Yg in. per minute. Readings were taken 
for each 1/10 in. of compression, the 
closure being continuous, with no stops 
except where sudden changes in load oc- 
curred. 

In many gears, when being closed at a 
slow speed, the resistance will build up at 
an abnormal rate, and shortly, from some 
reason such as the elasticity of the parts, a 
sudden readjustment will occur. In many 
instances this is accompanied by a loud re- 
port that may be best described by use of 
the word "bombardment." Invariably such 
readjustment results in a sudden reduction 
of the load. When a bombardment oc- 
curred during the tests, the machine was 
stopped until a full record of the condi- 
tions could be obtained. In plotting the 
static test diagrams the actual results have 
been used, all bombardment actions being 
shown, and no curves having been aver- 
aged or smoothed out, as is frequently done 
in plotting such diagrams. No gear should 
be condemned, however, solely because of 
the presence of bombardments or irregular 
action in the static tests, for some gears, 
while showing very irregular static 
diagrams, and even total failure in this 
slow test will yet show excellent results 
in both the drop test and the car-impact 
tests. Bombardments are conceded to be a 
normal action of many types of gears in 
slow static testing. 

The car-impact tests show that when cars 
are coupled at a velocity of four miles per 
hour, each of the two opposing draft gears 
begins to close at a rate of 2112 in. per 
minute (176 ft. per min.) and that the 
closing rate gradually falls off until it is 



zero at the point of maximum gear closure, 
this corresponding with the point where 
both cars are of equal velocity. The aver- 
age rate of closure at four miles per hour 
impact is approximately 1400 in. per min- 
ute; the static test rate of % in. per minute 
exists for less than 1/100 in. of gear move- 
ment. Results of slow static tests cannot 
therefore be compared with service or im- 
pact tests. The static is the simplest and 
the easiest draft gear test to make, and it is 
probably understood by the average me- 
chanical man better than any other. It is 
unfortunate, therefore, that it is not more 
reliable, but as will be seen as the various 
tests are discussed, it is usually misleading 
and cannot be employed for comparing the 
merits of different draft gears. 

The practice of rating gears upon a sup- 
posed ultimate resistance such as, for ex- 
ample, "a 200,000 lb. gear" or "a 350,000 
lb. gear," is to be discouraged. Due to the 
limited travel of draft gears it is necessary 
that the ultimate resistance of the gear be 
high if cars are to be handled at switching 
speeds above two miles per hour. The man- 
ner in which this ultimate resistance is 
reached is of great importance. It will be 
seen in some of the static cards that while 
the ultimate resistance is high, yet at the 
beginning of the diagram it is extremely 
low and becomes really effective only dur- 
ing the last quarter of the diagram. This 
means not only that the gear is of low 
capacity for its ultimate resistance, but that 
the final rate of building up the force is 
too high and will set up undesirable vibra- 
tions in the car structure. The ultimate 
resistance of a gear cannot, therefore, be 
wholly indicative either of capacity or of 
cushioning value, capacity being a product 
of the average force and travel, and cush- 



36 



Draft Gear Tests of the U. S. Railroad Administration 



37 



ioning being dependent upon the rate of 
building up of the force as well as the 
magnitude of the force itself. 

Static test diagrams have been plotted 
for closures at the rate of % in. per min- 
ute and are reproduced in Figs. 18 to 35, 
inclusive, at the end of this chapter, on the 
same sheets with the drop test diagrams. 
The same gears were also partially closed 
at the rate of % in. per minute and at an 
average rate of 3 in. per minute, for com- 
parison. These three closures were made 
in immediate succession so that the condi- 
tion of the gear had not changed. 

A discussion of the individual perform- 
ance of the gears in the static tests follows: 

Westinghouse D-3 

Gears No. 1 and 2 

The action of these gears during com- 
pression was smooth and regular, with an 
occasional clicking, but no noticeable fall- 
ing off in load. On the release, in each in- 
stance some slight tendency to stick was 
observed. No failure of any parts of the 
gears occurred in these tests. The effect of 
the preliminary spring action is noticeable 
in both diagrams, but in neither instance is 
there shown the customary flattened top to 
these curves, which ordinarily results from 
the functioning of the pressure limiting 
feature. 

Westinghouse NA-1 

Gears No. 4 and 5 

The static test was attempted on two 
gears only of the above type, gears No. 4 
and No. 5. This was made at a speed of % 
in. per minute and in each instance the re- 
sistance built up to such an extent at this 
slow speed that the gears were destroyed. 
The failures occurred by bulging and 
shortening of the barrel and by breaking 
the supporting ends off the stationary fric- 



tion plates or spacers. In each instance 
the gears failed to such an extent that they 
were eliminated and gears No. 6 and No. 7 
substituted for the further tests. No at- 
tempts were made to conduct static tests on 
gears No. 6 and No. 7. 

These failures in the slow static test at a 
speed of % in. per minute do not neces- 
sarily disqualify the type of gear, as in the 
later car-impact tests the average rate of 
gear closure was approximately 1450 in. 
per minute, or 11,500 times as rapid as in 
this static test. Furthermore, these high 
resistances were not found in the car-im- 
pact tests. 

Sessions K 
Gears No. 9 and 10 

Two gears only of this type, gears No. 9 
and No. 10, were subjected to the static 
test, as one of them, gear No. 9, failed in 
the test. This failure was similar to that 
of the previously discussed Westinghouse 
NA-1 gear and the same remarks apply. 
The failure was by bulging and shortening 
of the barrel and bending and elongation 
of the friction box. The friction faces after 
the test were found to be badly galled and 
drawn. This gear was eliminated and gear 
No. 11 substituted for the tests. 

The action of these Sessions K gears in 
the static test was Unusual. This gear 
usually bombards badly and often requires 
sledging to keep it moving when being 
subjected to static tests. In the present in- 
stance the action was smooth and without a 
single bombardment. On attempting to 
release gear No. 10, however, it was found 
to be stuck, and sledging was resorted to 
in order to start the release. From this on 
the release line was smooth. After this 
test the friction surfaces of the gear were 
found to be galled and drawn. Such action 
indicates that either the friction blocks or 
box were made of extremely soft material. 



38 



Draft Gear Tests of the U. S. Railroad Administration 



Sessions Jumbo 
Gears No. 13 and 14 

The performance of these gears in the 
static test was typical of static tests gen- 
erally. Gear No. 13 developed many light 
bombardments. Gear No. 14 creaked con- 
tinually while being compressed, but 
showed no falling off in load of any mag- 
nitude. The action of both gears on re- 
lease was good. The fact that one of these 
gears showed so much greater ultimate re- 
sistance and capacity than the other in this 
test is undoubtedly due to the condition of 
the friction surfaces. 

Cardwell G-25-A 

Gears No. 16 and 17 

These gears closed reasonably smoothly 
in the static test, there being a continual 
creaking but no falling off in load of any 
magnitude. In each gear a small corner 
was broken off of one of the triangular 
friction blocks during this test. After the 
test the friction surfaces were found to be 
somewhat galled. Gear No. 16 stuck at one 
point on the release, but snapped loose, 
and the remainder of the release was 
smooth. These gears each had a very heavy 
initial compression and this is shown in the 
beginning of the curves. 

Cardwell G-18-A 

Gears No. 19 and 20 

The action of these gears in the static 
test was good, there being no bombard- 
ments, but a continual creaking. The re- 
lease was steady and the friction faces after 
the tests were in good condition. Gear No. 
19 had a heavier initial compression than 
gear No. 20, and this is reflected in the 
curves. 



Miner A-18-S 

Gears No. 22 and 23 

These gears in the static test showed 
smooth action both on compression and re- 
lease, there being neither bombardments 
nor creaking. The friction faces after the 
tests were in good condition. The heavy 
initial compression of these gears is evi- 
dent in the diagrams. 

Miner A-2-S 
Gears No. 25 and 26 

The action of the two gears of this type 
tested was quite different, as can be seen 
from the diagrams, gear No. 25 being of 
much less ultimate resistance and capacity 
than gear No. 26. In the drop tests imme- 
diately preceding, however, the two gears 
were of equal capacity. The action of both 
gears was smooth except near the closing 
point of gear No. 26, where the load be- 
came irregular. No bombardments or 
creaking accompanied this change in load. 
On release the action was smooth in both 
instances. Both gears had heavy initial 
compression. 

The results obtained from the static tests 
of these two gears illustrate forcibly a fact 
frequently noticed: that a slight change in 
the condition of the friction surfaces may 
not materially affect the action of the gear 
in the drop test and yet entirely change the 
results in the static test. 

National H-l 

Gears No. 28 and 29 

The static tests of these gears are espe- 
cially interesting. Gear No. 28 showed a 
very low ultimate resistance when being 
closed at a speed of )/% in. per minute and 
in the succeeding tests, as the closing speed 
was increased the resistance increased; be- 
cause of this the three compression lines 



Draft Gear Tests of the U. S. Railroad Administration 



39 



are shown on the static diagram. In the 
case of gear No. 29, the resistance at Y% in. 
per minute built up beyond the capacity 
of the 600,000 lb. testing machine. Yet in 
the drop tests the two gears were of prac- 
tically equal capacity. This action was 
undoubtedly due to friction surface condi- 
tions that could not be detected, and the 
results further confirm the idea that a 
slight deposit upon the friction surfaces 
may materially influence the static tests, 
but that higher speed tests may not be af- 
fected to the same degree. This is of spe- 
cial importance when it is considered that 
in service the highest draft gear capacity is 
needed at the highest closing speeds. 

Two bombardments occurred during the 
closing of gear No. 29. The release of both 
gears was smooth. 

National M-l 
Gears No. 31 and 32 

The action of these gears in the static 
test was good. Two slight bombardments 
occurred during the closing of gear No. 31, 
but none in the case of gear No. 32. The 
release of both gears was smooth. 

National M-4 
Gears No. 34 and 35 

These gears bombarded during the static 
tests and in each instance a bombardment 
occurred near the point of closure, so that 
the resistance had no opportunity to again 
build up before the end of gear travel was 
reached. The figures given in Column 5 
of the table, Fig. 17, are for the maximum 
resistances, namely, 358,000 lb. and 349,- 
000 lb. The results in Columns 3 and 4, 
however, are for resistances at the end of 
gear closure. It will be understood that in 
another test bombardments might occur at 
other points or even disappear entirely. 



Murray H-25 

Gears No. 37 and 38 

The action of these gears in the static 
test was regular and smooth, there being no 
bombardment or creaking. The release 
also was smooth and positive. These static 
cards are among the smoothest and most 
regular obtained from friction gears. 

Gould 175 
Gears No. 40 and 41 

These gears in the static test closed by 
means of a continued series of light bom- 
bardments, as reproduced in the diagrams. 
At the beginning of the release a tendency 
to stick occurred in each gear, this being 
reflected in the release curves. 

Bradford K 
Gears No. 45 and 46 

The static tests of these gears, while 
smooth and regular, show but little re- 
sistance for a friction gear, and practically 
no friction. The release is positive, but of 
such a character as to indicate very little 
absorption of energy. 

Waugh Plate Type 
Gears No. 48 and 49 

The action of these gears was smooth 
and regular. Gear No. 49 showed prac- 
tically no resistance during the first % in. 
of compression. The release was positive 
and smooth. Each of these gears took a 
permanent set of approximately % in. dur- 
ing the static test. 

Christy 
Gears No. 51 and 52 

These were the most erratic gears in the 
static tests. Gear No. 51 gave one violent 
bombardment after another, and also stuck 



40 



Draft Gear Tests of the U. S. Railroad Administration 



at one point on the release. Gear No. 52 
stuck on the compression and could not be 
closed in the 600,000 lb. machine. . The 
barrel of the gear started to fail and the 
final yield shown in the curves is not due 
entirely to movement of the friction parts, 
but partly to shortening of the barrel. The 
friction surfaces were found to be badly 
galled and drawn after the test. 

Harvey 8 in. x 8 in. Springs 

Gears No. 54, 55 and 56 

Each of these gears as tested consisted of 
two 8 in. x 8 in. Harvey springs set side by 
side in the testing machine. It will be 
noticed that most of the resistance is in the 
later portion of the travel and increases 
abruptly. One heavy bombardment oc- 
curred during the test of gear No. 55, this 
incidentally showing that the Harvey 
springs are actually friction mechanisms. 
The release lines, which are smooth and 
regular, also show that friction is present. 
The absorption, however, is low. 

A. R. A. Class G Springs 

Gears No. 57, 58 and 59 

Each of these gears as tested consisted of 
two 8 in. x 8 in. Class G springs set side by 
side in the testing machine. The diagrams 
obtained show typical coil spring action, 
there being a slight amount of absorption 
due to hysteresis and to the friction of the 
free ends of the spring against the faces of 
the testing machine. 

Summary of Static Tests 

The results of the static tests are shown 
in the table, Fig. 17. For comparison 
there are shown also the results obtained 
in the drop test and the later car-impact 
tests for the same gears. It will be noticed 
in general that the resistances as given are 
in excess of figures commonly reported for 



gears of the same types. This may be due 
to the fact that the friction surfaces in these 
tests were in good condition and that all 
gears had identical treatment. The follow- 
ing description of the several columns' of 
this table will serve to explain it more 
fully: 

Column 1 is self-explanatory. 

Column 2 identifies the test gears by 
number. 

Column 3 gives, for a closing speed 
averaging 3 in. per minute, the ultimate or 
maximum resistance of the gear at the 
point where the gears just closed or where 
normal gear action ceased. Columns 4 and 
5 give the ultimate resistance, at closing 
speeds of % in. and % in. per minute. An 
asterisk (*) in any of these columns de- 
notes that the maximum resistance as tabled 
was developed before the gear was closed, a 
bombardment or other cause reducing the 
resistance at the point of closure. It will 
be understood that the capacity of the test- 
ing machine would not admit of complete 
closures at the 3 in. and % in. speeds. The 
results have been extended proportionately, 
however, so that the tabulated results rep- 
resent complete gear closures. 

Columns 6 and 7 give the work done and 
the work absorbed by the gears in the static 
test at the % in. per minute closure. 

Columns 8 and 9 give for comparison 
the work done and work absorbed by the 
same gears in the drop test. 

Column 10 gives a computed resistance 
for the drop test. This figure has been ob- 
tained by proportioning the resistances to 
the foot-pounds of work done in these two 
tests. Thus in gear No. 1, the static test at 
% in. per minute gave an ultimate resist- 
ance of 190,000 lb. with 18,434 ft. lb. of 
work done. In the drop test the work done 
was 13,875 ft. lb.; hence on the same basis 
the ultimate gear resistance is 143,000 lb. 
The figures in this column therefore, al- 



Draft Gear Tests of the U. S. Railroad Administration 



41 



though purely hypothetical, are of interest. 
If the static card is indicative of the dy- 
namic force curve, then the results in Col- 
umn 10 are approximately correct, for in- 
asmuch as the one leg (gear travel) is the 
same in both diagrams, the other leg (re- 
sistance) should be roughly proportional 
to the area, or work done. 

Columns 11 and 12 give the work done 
and work absorbed by the same gears in 
the later car-impact tests at Rochester. 

Column 13 gives the ultimate resistance 
figures obtained for these gears in the car- 
impact tests. 



The resistance figures given in this table 
thus represent a variety of speeds and con- 
ditions of gear closure, the static closures 
being at a constant speed and the drop and 
car-impact closures beginning at a high 
speed, which gradually reduces to zero at 
the point of maximum closure. In the car- 
impact tests, with a gear in each car, the 
gears begin to close at a speed not less than 
1056 in. per minute at 2 miles per hour 
impact, or 2112 in. per minute at 4 M.P.H. 
impact. In the drop test, with a 15 in. free 
fall, the gears begin to close at a speed of 
6458 in. per minute, or 9130 in. per minute 
at 30 in. free fall. 



42 



Draft Gear Tests of the U. S. Railroad Administration 







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9,000 LB. DROP TESTS 

Friction Surfaces Coated with Foreign Material 



It has been repeatedly noticed when 
taking down gears in car repair yards that 
the friction surfaces, while usually worn to 
a good bearing contact, are not in the same 
clean and perfect condition as that of pro- 
tected test gears. On the contrary, there is 
frequently found an actual coating or glaz- 
ing of hard, black material that can some- 
times be scraped off with a knife. This 
is probably an accumulation of particles 
of metal, coal dust and rust. 

In order to obtain some knowledge of 
the effect of foreign material upon the 
friction surfaces, one of each type of gear 
was taken apart, after completing the orig- 
inal drop and static tests, and the friction 
surfaces were dampened and sprinkled 
with a mixture of pulverized coal and iron 
rust. The gears were then reassembled 
with the parts in their original positions 
and the dampness allowed to dry out. Each 
gear was then put under the 9,000 lb. drop 
and the closing point determined in as few 
blows as possible, and the gear then given 
12 blows at or just below the closing point. 

The gear was then taken apart and the 
free material wiped off with clean waste. In 
almost every instance the friction faces 
were now found to be covered with a hard, 
glazed coating similar to that found in 
service. This was removed with clean, 
sharp sandpaper and the surfaces again 
wiped off with clean waste. This in every 
instance left the friction surfaces in as per- 
fect looking condition as could be desired. 
The action of the gears immediately after 
this is therefore especially interesting, as 
in almost every case the careful cleaning of 
the surfaces did not increase the capacity, 
and quite a number of blows were required 



to restore the gears to their original capa- 
cities. In several instances it was impos- 
sible to entirely restore the gears. It will 
be seen from a study of the results of these 
tests that any gear might by this method 
be made to show an extremely low capa- 
city, even though all parts of the gear were 
of full size and to gage and the friction 
surfaces apparently in perfect condition. 
At the same time, an inferior gear could be 
in apparently no better or more favored 
condition and yet show decidedly higher 
results. 

The table, Fig. 36, has been prepared to 
show the results of this test, and the fol- 
lowing paragraphs will more completely 
explain the values given in the several 
columns. 

Column 1 is self-explanatory. 

Column 2 identifies the single gear of 
each type used for this test. 

Column 3 gives for ready comparison 
the original total fall required to close this 
same gear. 

Column 4 gives the total fall required to 
close the gears when first operated with the 
mixture upon the friction surfaces. 

Column 5 gives the total fall required to 
close the gears with coated friction sur- 
faces, but after receiving 12 blows. 

Column 6 gives the total fall required to 
close the gears immediately after sand- 
papering and thoroughly cleaning the fric- 
tion surfaces. 

Column 7 gives the number of blows 
that had to be given each gear to restore it 
to its original capacity as given in Column 
3. In this work of restoration each gear 
was operated until the original capacity 



62 — 



Draft Gear Tests of the U. S. Railroad Administration 



63 



A/A/CE AA/D 

TYPE of 

GEAR 




TOTAL FALL OF 3000 LBS WEIGHT TO CL05E 


AimBER OF 
BLOWS REQUIRE 
TO RESTORE 
GEARTO 0RIG- 
lA/AL CAPACITY 

AFTER CLEAN- 
ING SURFACES 


REMARKS 


/N 
QfflGML 

cm/r/w 


W/TH COATED 
SURFACES 


FIRST 
CLOSURE 

AFTER CLEAN- 
ING SURFACES 


F/R5F 
CL05//RE 


AFTER 
TWELt/E 
BLOWS 


(/) 





» 


W 


(4> 


<® 


<Z> 


(<s) 


WE5T/MGHOUSE 
D-3 


/ 


18.50" 


/0.50 " 


Z0.5 " 


//.5" 


/S 




WESTINGHOUSE 
A/A-/ 


6 


21.06" 


13.06 * 


14.06 


/4/ " 


41 




SE5S/ONS 
A 


10 


10/7" 


d.Z " 


9.2 


/3.Z " 


f 5.2 After 
30bfo*vs 


Gear cou/d nof be 
fo/fy restored. 


5E5S/OA/S 
OUMBO 


13 


zejo" 


/6J " 


Z6.Z 


ZZ/' 


ZS.FAfter 
35 b/o*ve 


Gear cou/d no/ be 
fuZZy resfot-e-d. 


CARDWELL 
G-2S-A 


16 


Z/.75" 


Z5.75 " 


Z2.75" 


Z8.8" 


28 




CARDWELL 
G-/6-A 


/9 


2025" 


Z3.25" 


17.00" 


/1.75" 


30 




Af/A/ER 
A -/OS 


22 


nffl" 


//5/ " 


//.5/ " 


/Z.5 " 


40 


- 


Af/A/ER 
A -2-5 


25 


f355" 


755" 


7.55 " 


/OS " 


27 




MAT/ONAL 


2d 


3/53" 


(55 " 


/7.5 " 


/7.5 " 


34 




A/AT ZONAL 
A?-/ 


3/ 


f8.52" 


352 " 


13.52 " 


f3.5" 


/7 




NAT/OAJAL 
A4-4 


34 


fS.54" 


854" 


/4.50 " 


/6.00" 


4 




MURRAY 
H-25 


37 


11.65" 


S.7 " 


/0.7 " 


//.7 " 


54 


No hard coating on surfaces 
as in other gears, but 
considerab/e. wear- 


GOULD 
/73 


40 


/83d" 


//At " 


ff.4 " 


/3.4 " 


52 




BRADFORD 
ft 


45 


//.iff' 


35 " 


3 5 " 


fOJ" 


ZZ 




WAUGH 
PLATE 


4d 


/4J7" 


ZZ.2 " 


//.2 " 


//.Z" 


/22"Affer 
/5 bZows 


Gear cou/d not be 
fv//y restored. 


CHR/5TY 


5/ 


/43Z" 


33 ' 


3.3 " 


/0.3 " 


dO 




HARVEY 

2-8 "x 8" SPGS. 


54 


7.88" 


5.9 " 


5.3 " 


6.9" 


/3 




CO/L 3PR/A/G5 
2-6x8-CLASS G 


A. R.A.Springs nof inc/uded in this test. 





Fig. 36 — Performance of Gears with Coated Friction Surfaces (Drop Test) 



was restored or until three successive blows 
resulted in no increase of capacity. 

It will be understood that the blows 
given in these tests were kept within the 
capacities of the gears, the general practice 



being to work the gears slightly below the 
solid point rather than above it. 

The results of these tests indicate that 
while new gears in laboratory tests may 
show acceptable capacities, depreciation 



64 



Draft Gear Tests of the U. S. Railroad Administration 



may occur in service, not only from even- 
tual wear, but from an immediate coating 
of the friction surfaces. Iron rust and coal 
dust, with or without sweated friction sur- 
faces or rain, will undoubtedly greatly re- 
duce the capacity of a gear in service as in 
these tests. It has not been possible to in- 
vestigate this as thoroughly as desired, but 
some little work of this character has been 
done in conjunction with the Engineer of 
Tests of the Norfolk & Western Railway. 
Experiments were made upon five different 
types of gears which had been in service 
for approximately three years each on 



as possible, after which a building up or 
restoration test was made by giving the 
gear additional blows until no further in- 
crease in capacity could be obtained. No 
attempt was made to clean the surfaces of 
these gears prior to the building up tests, 
as the test was intended to develop what 
recovery might be effected by simply work- 
ing the gear. The gears were all in good 
condition as to wear, and would in every 
instance have been so declared upon sur- 
face inspection. The results of these tests 
are shown in the table, Fig. 37, a descrip- 
tion of the columns of which follows: 



AVsffYE AA/D 

TYPE or 

GEAR 


k: * Q 
S F ff 


AVERAGE RESULTS- 9000 LB5.DR0P 


DROP TEST 

VALUE OF 

NEW GEAR 

TOTAL. 
FALL 


TOTAL FALL 
REO.O. TO 
CLOSE GEARS 
WHEN FIRST 
REMOVED 


GEAR 
RESTORED 

TO- 
TOTAL 
FALL 


tfUMBEH 

OF BLOWS 

NECESSARY 

FOfit 
RESTORATION 


(/) 





<3> 


CO 


@ 


® 


M/A/ER 
A-/8-A 


/O 


/9.9" 


16.4' 


17.5" 


/(? 


M/A/ER 
A -59 


z 


27.0" 


18.0" 


20S" 


32 


SESS/ONS 
R 


2 


13.3" 


8.6" 


3.0" 


/4 


SE3S/OA/S 
JUMBO 


2 


28.1" 


15.0" 


/6.S" 


2/ 


A/A T/OA/AL 
H-l 


/O 


3/. 2" 


/9.4" 


26.9" 


32 



Fig. 37 — Drop Tests of Friction Gears Which Were Taken Out of Service, 
Norfolk & Western Railway 



N. & W. 100-ton coal cars. The gears were 
carefully removed from the cars so as not 
to disturb the deposit and glazing on the 
friction surfaces and were put in tight, in- 
dividual boxes and carried immediately to 
the drop test machine. The actual fall re- 
quired to close the gears in their service 
condition was determined in as few blows 



Column 1 — In this column the gear types 
are identified, and in explanation the Miner 
A-18-A gear is the same as the Miner 
A-18-S of the U.S.R.A. tests, except that 
the A-18-A has 3 in. travel and the A-18-S 
has 2y 2 in. travel. The Miner A-59 gear 
is an especially long gear, not usable in the 
standard pocket and hence not included in 



Draft Gear Tests of the U. S. Railroad Administration 65 



the U.S.R.A. tests. The Sessions K, the 
Sessions Jumbo, and the National H-l are 
identical with the same types in the U.S. 
R.A. tests. 

Column 2 — This column indicates the 
number of gears carried through the N. & 
W. tests. 

Column 3 — This column gives for ready 
reference the total average drop test value 
of the several types, when new and in good 
condition, as found in the U.S.R.A. tests. 
The Miner A-18-A is taken the same as the 
A-18-S. For the Miner A-59 a value is 
taken from previous tests of these gears. 

Column 4 — This column gives the aver- 
age total fall, including the travel, re- 
quired to just close the gears when first 
tested after removal from service. These 
figures therefore represent the value of the 
gear as in actual service, after a period of 
three years' use, as heretofore explained. 

Column 5 — This column gives the aver- 
age total fall to which it was possible to 
build up or restore the gears. 

Column 6 — This column gives the aver- 
age number of blows necessary to restore 
the gears to the falls given in Column 5. 

In this test the Sessions gears, which 
have the friction elements of unhardened 
cast iron working against unhardened 
forged steel, showed the greatest percen- 
tage of depreciation and the least restora- 
tion. The National gear, which has hard- 
ened steel friction elements working to- 



gether, showed the next greatest percentage 
of depreciation and the greatest restoration. 
The Miner gears, which have hardened 
steel friction shoes working against a mal- 
leable iron barrel, showed the least per- 
centage of depreciation and necessarily the 
least percentage of restoration. It does not 
thus appear that the character, and partic- 
ularly the hardness of the friction surfaces, 
influenced this depreciation. On the other 
hand, the Miner gears were under a heavy 
initial compression in the cars and the 
Sessions and National under practically 
none. It is therefore probable that the 
tightness of the friction parts may have 
prevented the entry of the foreign material 
in the case of the Miner gears. In the case 
of these N. & W. gears, the friction shoes in 
the Miner gears were in every instance tight 
with the gears in position in the cars, while 
the friction members were loose in every 
one of the Sessions and National gears. As 
no measurable wear had occurred in the 
National gears the manufacturers offer in 
explanation of this loose condition of the 
friction members that an inferior lot of 
springs had been used, with consequent set 
and loosening of the friction parts in the 
car. In the case of the Sessions gears the 
designs provide for loose friction blocks in 
the car. Further investigation along the 
lines of gear depreciation, due to foreign 
material on the friction surfaces in service, 
should be made. 



DESTRUCTIVE TESTS 



Immediately after the tests with coated 
friction surfaces, the same gears, one of 
each of the types included in the program, 
were tested to at least partial destruction 
under the 9,000 lb. drop, the gears being 
supported on a solid anvil. In each in- 
stance successive blows were given from 
heights beginning at 1 in. free fall of the 
weight and increasing by 1 in. increments, 
a record being made of the point at which 
each gear went solid and of the point at 
which destruction began, as evidenced by 
scaling, fracture, bending or shortening of 
some part of the gear. These tests are of 
the kind best suited to show the ability of a 
gear to receive over-solid blows and are 
designed to penalize weakness instead of 
putting a premium upon it, as set forth in 
a preceding chapter of this report. It will 
be noticed that some of the gears begin to 
show evidence of distress at a fall of just a 
few inches above the solid point. 

A discussion of the individual perform- 
ance of the gears in the destructive tests 
follows: 

Westinghouse D-3 
Gear No. 1 

This gear in the destructive test went 
solid at 16 in. free fall, and at 20 in. free 
fall a number of fine cracks were observed 
at the tops of the convolutions that occur 
near the lower end of the barrel. The gear 
was given seven more drops, the last one 
being a free fall of 27 in. The cracks in 
the barrel had now opened up and the bar- 
rel had bulged at the point of the cracks to 
9% in. diameter, whereas the diameter 
here before the test was 9 in. The barrel 
had shortened % in. Neither the free 
height nor the friction height of the gear, 



however, was reduced, as neither the fric- 
tion spring nor the preliminary spring had 
taken permanent set of any consequence. 
The travel of the gear had increased from 
2y 2 in. to 3% in., due to the shortening of 
the barrel. This increased travel, it should 
be noted, is accompanied under these ex- 
traordinary circumstances by what would 
undoubtedly prove, upon repetition, to be a 
disastrous deflection of the friction springs. 
A destructive value of 23.8 in. has been 
given this gear, this figure being deter- 
mined by the general rule outlined at the 
close of this chapter. 

Westinghouse NA-1 
Gear No. 6 

This gear was carried up to a final blow 
of 36 in. free fall, the gear going solid at 
24 in. free fall. At 28 in. the barrel started 
to scale on the ends just opposite the slots 
in the sides of the ends of the friction 
spacers. At 34 in. the barrel showed a 
crack at the bottom of one of the key slots. 
After the test the free length of the gear, 
which is also the friction length, was found 
to have been reduced % in., being now 
t*$ in. less than the pocket dimension. 
The barrel had shortened % in., the gear 
travel remaining the same as originally. 
The slots for the spacer ends had been re- 
duced 1% in., making the spacers bind 
and causing the gear to stick at lighter 
blows. There was no evidence of spacer 
failures or of the barrel deforming beneath 
the spacer ends, as occurred in the static 
tests of gears No. 1 and No. 2 of this same 
type. The release spring had taken a set 
of % in. To this gear has been given a 
destructive value of 30 in. 



— 66 — 



Draft Gear Tests of the U. S. Railroad Administration 



67 



Sessions K 

Gear No. 10 

This gear was subjected to a maximum 
blow of 33 in. free fall. During the test 
the gear stuck and failed to release on a 
number of the lighter blows. The gear 
went solid at 13 in. free fall and at 15 in. 
free fall the barrel started to scale and to 
bulge. After this test the barrel was found 
to have shortened ^J in. and the friction 
box opening to have elongated fa in. 
The outer coil spring had taken a set of 
T % in. and the free length of the gear 
had been reduced by % in., being now % 
in. less than the pocket length and the fric- 
tion length 1% in. less than the pocket 
length. Because of the fact that this test 
gear, along with others of the same type, 
heretofore began to scale in the regular 
drop tests before the closing point was 
reached, the destructive value has been 
reduced below that denoted by this test, 
the destructive value being placed at 1 in. 
over the average solid value, or at 19.8 in. 

Sessions Jumbo 

Gear No. 13 

This gear was carried up to a final free 
fall of 30 in, going solid at 21 in. The 
barrel of this gear was slightly cracked 
through one of the rivet holes in the pre- 
ceding drop test and attention was there- 
fore particularly directed to this point dur- 
ing the destructive test. At 25 in. the crack 
started to widen. At 28 in. the friction box 
began scaling. At 29 in. the crack in the 
corner of the barrel had opened % in. and 
at 30 in. the weight recoiled and the gear 
jumped enough to allow the recurring fall 
of the weight to land upon the side of the 
gear, necessitating a discontinuance of the 
test. Upon measurement the gear was 
found to have shortened fa in. in free 
length and the friction box to have elon- 



gated fa in., the gear now being fa in. 
less in free length than the standard draft 
gear pocket. In view of the questionable 
crack developing in this gear prior to this 
test, the benefit of all doubt has been given 
it and its destructive value of 32.1 in. is 
based upon the point at which this crack 
first started to widen. 

Cardwell G-25-A 

Gear No. 16 

This gear was given drops up to and in- 
cluding a free fall of 32 in., the gear going 
solid at 18 in. free fall. At 20 in. six cracks 
had developed in the heads and at 22 in. 
ten cracks had appeared and the heads were 
deforming. After the test the gear was 
measured and it was found that the free 
length had been reduced y 2 in. and the 
solid length % in. The free length, how- 
ever, was still 1 in. greater than the stan- 
dard pocket dimension, this gear being 
nominally under a heavy initial compres- 
sion in the car, as heretofore explained. 
The heads had been badly deformed and 
cracked, and had each shortened an aver- 
age amount of fa in. The spring rod 
had bent fa in., due to the inertia of the 
springs and spring washers, and had elon- 
gated Yg in. The outer coil springs had 
taken an average set of % in. The friction 
blocks were not injured. To this gear has 
been given a destructive value of 20.9 in. 

Cardwell G-18-A 

Gear No. 19 

This gear was given successive drops up 
to and including a free fall of 32 in., the 
gear going solid at 17 in. free fall. At 20 
in. the top head began to fail and at 23 in. 
the top surface was depressed. At 26 in. 
three cracks had developed in the heads. 
This gear was in somewhat better condition 
at the completion of this test than the Card- 



68 



Draft Gear Tests of the U. S. Railroad Administration 



well G-25-A gear. A destructive value of 
22.6 in. has been given this gear. 

Miner A-18-S 
Gear No. 22 
This gear was given successive drops up 
to and including a free fall of 30 in. The 
gear in this test went solid at 14 in. free 
fall. At 19 in. free fall the springs went 
solid and at 21 in. free fall the barrel 
began scaling. At 23 in. the barrel began 
to bend out of line and at 27 in. a crack 
appeared. After the test the free length of 
the gear was found to have decreased % in. 
and the barrel to have shortened -j 5 g in., 
the free length of the gear being now *4 in- 
less than the standard pocket dimension. 
There was no breakage of center wedge, 
friction shoes or rollers. To this gear has 
been given a destructive value of 26.9 in. 

Miner A-2-S 
Gear No. 25 
This gear was carried up to a final blow 
of 36 in. free fall, the gear going solid at 
10 in. free fall. At 19 in. one friction shoe 
flaked and showed a slight crack. At 20 in. 
the barrel began scaling and at 24 in. 
bulging of the barrel could be detected. 
At 29 in. one crack developed in the fric- 
tion end of the barrel and at 30 in. a second 
crack developed here. After the test the 
free length of the gear was found to have 
been reduced by l T X g in., being now 
■£f in. less than the standard pocket 
length. The friction length was 1 in. less 
than the pocket length. The barrel had 
bulged and shortened % in. and the outer 
coil spring had taken a set of ^f in. 
The friction end of the barrel had opened 
slightly and the two cracks mentioned had 
developed in this portion of the barrel. 
The friction shoes were each cracked in the 
roller seats and were cracked and flaked at 
the ends. The rollers had hammered and 
seated into the shoes and the center wedge, 



but the rollers were not injured. To this 
gear has been given a destructive value of 
20.2 in. 

National H-l 

Gear No. 28 

This gear was given successive drops up 
to and including a free fall of 60 in. in an 
unsuccessful effort to fracture or deform 
some part essential to the operation of the 
gear. It went solid at a free fall of 31 in. 
At 48 in. two of the columns showed bend- 
ing and at 52 in. all four columns were 
bent. At 49 in. the friction spring went 
solid and the center post of the gear came 
into action. At 54 in. the friction blocks 
had become loose. Upon measurement after 
the test the center post of the gear was 
found to have shortened -iq in. and the 
friction spring had taken a set of -f^ in. 
The free length of the gear had been re- 
duced y 8 in. and the length when the fric- 
tion shoes tightened had also been reduced 
y 8 in. The gear length at this latter point, 
however, was still % in. in excess of the 
standard pocket dimension and the free 
length % in. in excess of it, so that this 
gear after the test would have been under 
y± in. total compression and % in. friction 
compression in the car. The corner posts 
had shortened % in. and the travel of the 
gear had consequently been increased by 
this amount. The gear was not damaged 
in this test except for the set of the spring 
and the shortened and bent corner posts, 
which, incidentally, are simply round steel 
bars of 1% in. diameter by 19% in. long 
and could be readily straightened. The 
gear after this test was entirely serviceable. 
In view of the fact, however, that the col- 
umns bent at a point 17 in. above the solid 
point of the gear a destructive value of 
48.2 in. has been given this gear. The 
ability of this gear to withstand punish- 
ment is very remarkable. 



Draft Gear Tests of the U. S. Railroad Administration 



69 



National M-l 
Gear No. 31 

This gear was tested up to a final free 
fall of 48 in., going solid at 17 in. free fall. 
At 27 in. one of the columns started to bend 
out of line and at 35 in. three columns were 
bent, the fourth one bending at 39 in. At 
42 in. the center post came into action and 
at 44 in. the spring went solid and the fric- 
tion shoes loosened. After the test the col- 
umns were found to have bent 1 in. out of 
line and shortened j$ in. The friction 
spring had taken a set of % in. and the 
center post had shortened T 5 g in. The 
free length of the gear had not been re- 
duced, but the length at which friction 
starts had been reduced jq in., this length 
being now the same dimension (24% 
in.) as the standard draft gear pocket. Ex- 
cept for the bent corner posts, the gear was 
suitable for service after this test. Inas- 
much as the first of these started to bend at 
a drop of 10 in. above the solid point, this 
gear has been given a destructive value of 
29.2 in. This gear, like the National H-l, 
shows exceptional ability to withstand 
severe punishment. 

National M-4 
Gear No. 34 

This gear was given successive blows up 
to and including a free fall of 48 in., the 
gear going solid in the test at 17 in. At 23 
in. three columns were bending. After the 
completion of the test, all four columns 
were bent approximately Jf in. out of 
line and one of the heads had a small crack 
in the column guide, due to the bent col- 
umn. The center column had not come into 
bearing to assist in taking the solid blow 
and the spring had not gone solid, although 
it showed a set of % in. 

The absolute free height of the gear had 
been reduced by % in., but would still have 



been under compression in the car. The 
gear, after this test, would have been en- 
tirely serviceable except for the bent corner 
posts. 

In view of the fact that the corner posts 
began to show bending at 6 in. above the 
solid point, the destructive value of this 
gear has been set at 27.5 in. 

Murray H-25 
Gear No. 37 

This gear was given successive blows up 
to and including a free fall of 26 in., the 
gear going solid at 15 in. At 20 in. the 
side members began to scale and at 21 in. 
bulging could be detected. Also at 21 in. 
the spring went solid. Upon measurement 
it was found that the free length of the gear 
had been reduced % in., being now % in. 
less than the standard pocket length. The 
shouldered side members had shortened 
T 7 6 in. and had bent and bulged. The 
wedge-shaped openings in the heads had 
spread an average of % in. To this gear 
has been given a destructive value of 22 in. 

Gould 175 
Gear No. 40 

This gear in the destructive test was car- 
ried up to 32 in. free fall, going solid at 15 
in. free fall. At 19 in. free fall the barrel 
began scaling in the reduced lower portion 
and at 20 in. bulging of the barrel could be 
seen. At 26 in. the mouth of the barrel 
cracked slightly. After this test the barrel 
was found to have shortened % in. and the 
barrel mouth to have spread T 3 g in. The 
free length of the gear was reduced % in. 
and the friction length % in., the gear 
travel having been reduced from 2 T 7 g - in. to 
2 T % in. and the friction members having be- 
come loose, the free length being T % in. 
less than the standard draft gear pocket 
length and the friction length {$ in. 



70 



Draft Gear Tests of the U. S. Railroad Administration 



less. The outer coil spring had taken a set 
of T % in. To this gear has been given a 
destructive value of 22.1 in. 

Bradford K 
Gear No. 45 

This gear in the destructive tests was car- 
ried up to a final free fall of 24 in. The 
gear during the drop test immediately pre- 
ceding it had been given free falls up to 
and including 10 in. and at this point in the 
previous test the top head had cracked and 
had been deformed T 3 e in. All of the 
springs had been solid and had taken per- 
manent set. As the destructive test pro- 
ceeded the gear showed increasing failure 
and deformation. At the conclusion of the 
test the springs had taken a set of % in. 
and the gear had been shortened % in. The 
heads were badly cracked and deformed. 
To this gear has been given a destructive 
value of 11.8 in. 

Waugh Plate Type 
Gear No. 48 

This gear was given blows up to a final 
free fall of 32 in., the gear going solid at 
10 in. free fall. Some set of the plates had 
taken place at 12 in. and at 14 in. the gear 
was loose in the standard pocket by ■$$ 
in. No parts were broken, but the free 
height of the gear was reduced % in. and a 
number of the plates were given a notice- 
able camber. The gear, however, even 
though loose in the pocket, was serviceable. 
A destructive value of 15.9 in. has been set 
for this gear. 

Christy 
Gear No. 51 

This gear was given blows up to a final 
free fall of 42 in., going solid at 12 in. The 
barrel started scaling at 20 in. At 24 in. 
bulging of the barrel could be detected. 



After the test the barrel was found to have 
shortened % in., the free length of the gear 
having been reduced % in., being now 
|| in. less than the pocket length and 
the friction length lg 3 ^ in. less than the 
pocket length. The barrel was bulged 1% 
in. at points in its sides where the metal is 
cut away to provide space for the spring, 
seven cracks having developed in the barrel 
at these points. The outer coil spring had 
taken a set of *4 in. To this gear has been 
given a destructive value of 27.6 in. 

Harvey Springs 
Gear No. 54 

Two Harvey 8 in. x 8 in. friction spring 
units were set side by side, in twin fashion, 
and were given successive blows up to and 
including 40 in. free fall in an effort to 
break a spring. Except that at 32 in. a 
small corner of no consequence broke off 
the end of one coil, no breakage occurred. 
Set, however, was noticed much earlier. 
The friction coils when received were each 
8^8 in. in height, and at the beginning of 
this test were 8 in. and 8^ in. free 
height. After the 11 in. drop the friction 
coils both stood at 7-Jf in. height. After 
the 18 in. drop they stood at 7% in. 
and after the test at 7% in., each having 
taken 1 in. set during the test and being % 
in. less than the pocket length. To this 
gear (two 8 in. x 8 in. Harvey springs) has 
been given a destructive value of 14.5 in. 

Two A. R. A. Class G Springs 
Gear No. 57 

These springs were set up side by side, in 
twin fashion, upon the solid anvil of the 
9,000 lb. drop machine. During the reg- 
ular drop tests the springs took an average 
set of j 3 ^ in. Upon further testing more 
pronounced set occurred, at 6 in. free fall, 
the average being T 3 g in. per spring. Thev 



Draft Gear Tests of the U. S. Railroad Administration 



71 



Ma/TE AND 

Tyre of 
Gear 


Test 
Gear 
No. 


9000* Weight 


Develofe- 
ment 

OF 

/a/lure 


Avg.7utal/xll 

S000*WE/<5/iT 

Required To 
Close One 

Commercial. 

$$£§ OF THIS 


Destruct- 
ive Value 
Ass/gned 
To T///sType 
Of Gear 


Total Tall 

REq'D. TO 

CloseGear 
InTh/sTest 


Add/t/onal 
Fall Beyonc 
Clos/ngPo/nj 
Required lb 
Start /ailurl 


© 


® 


<d 


@ 


® 


<D 


© 


WEST/NG/iOUSE 
D-3 


/ 


18.5" 


4" 


RAF/D 


/9.3" 


23.8" 


WEST/NGHOUSE 
A/A-/ 


6 


2 7.0" 


4' 


RAR/D 


2 6.0" 


30.0* 


SESS/O/VS 
A* 


/O 


/5.2" 


2" 


RAPID 


18.3" 


19.8" 


SESSIONS 
JUMBO 


/3 


24./" 


4" 


SLOW 


2 8./ 


3 2./ 


CARDWELL 
G -26 -A 


/6 


2 0.8" 


2" 


RAF/D 


/ 8.9" 


20.9 


CARDWELL 
G-/8-A 


/9 


20.3" 


3" 


RAR/D 


19.6 


22.6 


M//VER 
A-/8S 


22 


/ 6.5" 


7" 


MED/UM 


/9.9" 


26.9 


M/NER 
A -2-3 


25 


/ 2.5" 


7" 


MED/UM 


/3.2" 


20.2" 


NAT/ONAL 


23 


33.5" 


/7" 


SLOW 


3/. 2" 


48.2" 


NAT/ONAL 


3/ 


/3.5" 


/O" 


SLOW 


/S.2"< 


29.2" 


NAT/ONAL 
M-4 


34 


/S.5" 


5* 


SLOW 


2/.S" 


27.5" 


MURRAY 
/i-25 


37 


/ 7 7" 


5" 


MED/UM 


/7.0" 


2 2.0" 


GOULD 
/75 


40 


/74" 


4" 


MED/UM 


/8./" 


2 2./" 


BRADFORD 


45 


/ /.5" 


/" 


RAP/D 


/O.Q" 


/ /.8" 


WAUG/i 
RLATE 


48 


/2.2" 


2" 


SLOW 


/3.S" 


/5.9" 


CNR/STY 


5/ 


/4.3" 


8" 


SLOW 


/S.6" 


27.6" 


HARVEY 
2-8"x8" SPSS. 


54 


7.3" 


5" 


MED/UM 


9.5" 


/<4.£" 


CO/L SPR/NGS 
2-8\8-CLA5S a 


57 


5.8" 


2" 


RAR/D 


5.8" 


7.8" 



Fig. 38 — Performance of Gears in Destructive Tests 



72 



Draft Gear Tests of the U. S. Railroad Administration 



were carried up to a final fall of 12 in. and 
at this point the average set was % in. No 
breakage occurred. 

A destructive value of 7.8 in. has been 
given for the two springs, but it should be 
noted that this is for conditions where the 
springs are not protected, but the coils are 
allowed to go solid. 

Summary of Destructive Tests 

The table, Fig. 38, has been prepared to 
show the results of these tests and to grade 
the gears as to destructive value. It is quite 
possible that a repetition of lighter blows 
would in each instance have produced fail- 
ure, but it is believed that no great error is 
made by this comparative grading. 

The several columns of the table are 
described as follows: 

Column 1 is self-explanatory. 

Column 2 identifies by number the gears 
that were subjected to this test. 

Column 3 gives the total fall required to 
close the gears during this particular test. 
In some instances this varies slightly from 
the figure obtained in the original drop 
tests, due usually to the fact that some of 
the gears could not be fully restored in the 
immediately preceding tests with coated 
friction surfaces. 



Column 4 gives the additional height 
from which the 9,000 lb. weight was drop- 
ped, reaching this by increments of 1 in. 
from the solid point, before visible distress 
of the gears began. 

Column 5 has been inserted to denote 
whether the failure from this point on de- 
veloped slowly or rapidly, under constantly 
increasing falls. 

Column 6 gives for reference the figure 
accepted as the average total fall required 
to close a new commercial gear of this type, 
when in good condition, this column being 
the same as Column 10, Fig. 16. 

Column 7 gives the comparative destruc- 
tive values assigned the several types. This 
figure is obtained by adding to the average 
drop test value of the type of gear as given 
in Column 6, the over-solid values in Col- 
umn 4. Thus in the case of the Westing- 
house D-3, gear No. 1 of this type was sub- 
jected to this test. During the test gear No. 
1 went solid at a total fall of 18% in. and 
at a total fall of 22y 2 in., or 4 in. above the 
solid point, the barrel started to fail. Ac- 
cordingly the destructive value of this gear 
has been set by adding 4 in. to the average 
total fall figure 19.8 in., giving a destruc- 
tive value of 23.8 in. The same practice 
has been followed for all gears. 



RIVET SHEARING TESTS 



The draft gears for the U.S.R.A. (United 
States Railroad Administration) cars were 
purchased on the requirement that they be 
of "150,000 lb. capacity" and the Mechan- 
ical Committee later defined a 150,000 lb. 
capacity draft gear in the following words : 

"A 150,000 lb. draft gear should be de- 
fined as one that will sustain a drop of 16 
in. (including travel of gear) of a 9,000 lb. 
weight, without shearing the rivets of one 
or both lugs, which are to be secured to 
suitable supporting members by nine % in. 
rivets of .15 carbon or under, driven in 
1% in. holes." 

A representative number of gears of each 
type used on U.S.R.A. cars were selected at 
random and subjected to the above test. 
The average of the results for each type was 
used to determine whether or not that type 
of gear met the terms of the specifications. 
In these tests the gears were supported 
upon a solid anvil and the weight was 
dropped from successive heights, increas- 
ing by 1 in. increments until the rivets 
sheared. 

In testing the Sessions K gears, the high- 
est capacity gears sheared the rivets at a 
lower drop than the lower capacity gears. 
In five instances the rivets sheared before 
the solid point of the gear was reached. In 
three instances the rivets sheared at the 
point of gear closure; and in but two in- 
stances did it require a blow from above the 
solid point to shear the rivets. In three in- 
stances the rivets were sheared at a point 
below the specification requirement when 
the successive blows by 1 in. increments 
were given the rivets. In each of the cases, 
however, when the gear was again set up 
and a single blow given from a height suffi- 
cient to produce a total fall of 16 in. the 
rivets did not shear. Thus, one of these 



gears, when given blows increasing by 1 in. 
increments, sheared the rivets at a total fall 
of 11 in., and when it was immediately 
thereafter given a single blow from a total 
fall of 16 in. the rivets were not sheared. 
The rivets in this re-test sheared at the next 
blow, or at a total fall of 17.2 in. 

For the Sessions gears it required on the 
average 2.7 in. less fall to shear the rivets 
than to close the gears. In the Westing- 
house D-3 gears the rivets usually sheared 
1 in. above the solid point, although in a 
few instances it required an over-solid blow 
of 2 in. to produce shear. In the Cardwell 
G-25-A gears it required on the average an 
over-solid blow of 3.2 in. to shear the 
rivets. In one instance a 4 in. over-solid 
blow was necessary. In the Murray H-25 
gears it required an average over-solid 
blow of 2.4 in. to shear the rivets. 

Considering the Westinghouse, Cardwell 
and Murray gears, it will be noted that the 
number of over-solid blows required to 
shear the rivets is in inverse relation to the 
over-solid sturdiness or destructive value of 
the gears as given in the table, Fig. 38. The 
short travel of the Sessions K gear necessi- 
tates a higher ultimate resistance, so that 
the elastic limit of the y 2 in. rivets is passed 
before the gear goes solid. In considering 
this test it should be remembered that 
the eighteen y 2 in. rivets ( T % in. when 
driven) have a shearing area of 4.47 sq. in., 
giving an ultimate shearing value of ap- 
proximately 189,000 lb., with an elastic 
limit in shear of approximately 135,000 lb. 
In practice the rear draft lugs each have 
twelve % in. rivets in }§ in. diameter 
holes, or a shearing area of 16.57 sq. in., 
with an ultimate shearing value of 700,000 
lb., or an elastic shearing limit of 500,- 
000 lb. 



73 — 



74 



Draft Gear Tests of the U. S. Railroad Administration 



The table, Fig. 39, has been prepared to 
show the results of these % in. rivets shear- 
ing tests made for the acceptance of gears 
for U.S.R.A. cars. 

In order to show for comparison how all 
of the gears perform in this test, and in 
order to study the specifications in the light 
of a full knowledge of each particular 
gear, one of each type of gear in the tests 
was subjected to the y 2 in. rivet shearing 
test. This was done after the car-impact 



Column 5 gives the actual amount of 
gear closure obtained in this test with the 
free fall of Column 4. 

Column 6 gives the total fall required to 
shear the rivets, this being the sum of the 
quantities in Columns 4 and 5. 

Column 7 denotes whether one or both 
lugs sheared, this, however, being of sec- 
ondary interest. 

In each of these tests the rivet samples 
were analyzed and the carbon content in no 



RESULTS OF £"R/VET SHE/?f?/NG TESTS. 
GEARS FOR US. R. A. CARS.- SOOOLB. DROP. 


WKE AND 

TYPE OF 

GEAR 


in 


TOTAL FALL TO CLOSe GEAR 


TOTAL FALL TO SHEAR RIY&S 


MAXIMUM 


M/NIMUM 


AVERAGE 


MA UMUM MINIMUM 


AVERAGE 


<Z> 


® 


0) 





® 


© 


(7) 


® 


WESTINGHOUSE 
D-3 


/<3 


21.6 " 


/6.6 " 


/S.9 


22.6 


13.6 " 


2/.o 


SESS/OA/S 
A 


IO 


23./" 


/S./ " 


ZO.S " 


22./ " 


f/.O " 


/7.S " 


CAROWELL 
G-25-A 


S 


tl.G " 


/&6 " 


/S.6 " 


ao.e " 


IS.S " 


/S.3 " 


MURRAY 
H-25 


7 


n.Q " 


/G.8 " 


ne " 


20.8 " 


n.e " 


20.0 " 



Fig. 39— Results of %-in. Rivet Shearing Tests. Draft Gears for U. S. R. A. Cars 

9,000-lb. Drop 



tests and was the final test given the gears. 

The results are given in the table, Fig. 
40, the several columns of which are de- 
scribed as follows: 

Column 1 is self-explanatory. 

Column 2 identifies by number the gears 
that were subjected to this test. 

Column 3 gives the original total fall re- 
quired to close each gear. During this test 
care was taken to see that all gears were up 
to this original capacity. 

Column 4 gives the free fall required to 
shear the rivets of one or both lugs. This 
height of fall was reached through succes- 
sive blows increasing by 1 in. increments. 



instance exceeded .15, the usual average 
ranging from .09 to .12. 

Some of these results will at first thought 
appear inconsistent, but a more careful 
study will show that the results in general 
are approximately what should be expected 
when gears of different travels and capaci- 
ties are tested upon undersized rivets. Thus 
the gears generally may be divided into 
two classes : those closing at four miles per 
hour or more in the car-impact tests and 
those closing at less than four 'miles per 
hour. Seven types as follows fall in the 
higher class: 



Draft Gear Tests of the U. S. Railroad Administration 



75 



AtAFE AND 

TYPE OF 

GEAR 


% 
II 












GO 


@ 


(?) 


fc> 


CO 


<® 


(7) 


WESTINGHOL/SE 
D-3 


2 


/S.fO" 


77" 


2.4T 


13.5 " 


ONE 


WESTINGHOUSE 
A/A-/ 


7 


ze.oo" 


2/" 


Z.66" 


23.7" 


BOTH 


SESS/ONS 


// 


20.06 


■ II" 


1.45" 


12.5 " 


ONE 


SESSIONS 
t/UMSO 


14 


27.06 


14" 


2.10" 


/6./ " 


BOTH 


CARDWELL 
G-2S-A 


17 


20.75" 


20" 


2.75" 


22.8" 


ONE 


CARDWELL 
G-/6-A 


ZO 


Id. 29" 


73" 


3.29" 


21.3 " 


ONE 


M7NER 
A-/S-S 


23 


/9.S2" 


77" 


2.47" 


/$«5" 


O/VE 


MINER 
A-2S 


275 


13. S3" 


//" 


2.53" 


13.5 " 


OA/E 


NATIONAL 


23 


32.50" 


9" 


LOO" 


10. " 


ONE 


NATIONAL 
M-/ 


3Z 


18.53" 


n" 


2.53" 


13.5 • 


ONE 


NATIONAL 
M-4 


J& 


23.46" 


17" 


2.30" 


/S.J " 


BOTH 


MURRAY 
H-25 


<?e 


(6.47" 


16" 


247" 


/6-S " 


BOTH 


GOULD 
77S 


4/ 


77.44" 


16" 


2.44" 


18.4 " 


BOTH 


BRADFORD 


46 


3.44' 


a" 


2.44' 


10.4 


one: 


WAUGH 
PLATE 


49 


13.25" 


ll" 


2.25' 


73.3 " 


ONE 


CHR/STY 


SZ 


'6.2/ " 


12" 


1.95' 


/4.0 " 


O/VE 


HARVEY 
2S"xQ SPSS 


ss 


/0. 76" 


6" 


1.76" 


3.8 " 


OA/E 


COIL SRR/ALGS 
2-Sx6-CIASS G 


56 


5.70" 


7" 


1.70 " 


3.7 " 


ONE 


SOLID STEEL 
BLOCK 






4" 




<4.0 ' 





Fig. 40 — Performance of Test Gears in %-in. Rivet Shearing Tests. 9,000-lb. Drop 



76 



Draft Gear Tests of the U. S. Railroad Administration 



National H-l. 
National M-l. 
National M-4. 
Miner A-18-S. 
Westinghouse NA-1. 
Sessions Jumbo. 
Sessions K. 

It will be noted that in no case did a 
gear of this class require an over-solid 
blow to shear the y 2 in. rivets. In six cases 
the rivets sheared before the gears went 
solid and in the remaining case the rivets 
sheared at the solid point. Furthermore, as 
might be expected, the gears of short travel 
usually sheared the rivets earlier than those 
of equal capacities and longer travel. 

A more clear understanding of this ac- 
tion will be had from the diagrams of Fig. 
41. At the top of this figure is shown a 
straight line diagram of a gear of 34.2 in. 
drop capacity and of S 1 /^ in. travel. The 
ultimate resistance of this gear is 189,000 
lb. and the eighteen y 2 m - rivets should 
shear at the same value, or just when the 
gear goes solid. Next there is shown a 
diagram of a 2 in. travel gear of the same 
ultimate resistance, 189,000 lb., and with 
this gear also the rivets should just shear 
at the solid point, but which in this case 
would be at 21 in. drop instead of 34.2 in. 
Next is shown the diagram of a gear of 2 
in. travel but of the same capacity (34.2 in. 
drop) as the 3% in. travel gear at the top 
of the figure. The ultimate resistance of 
the gear would in this case be 307,000 lb. 
and the rivets, which have the value of 
189,000 lb., should shear at 1.23 in. gear 
travel or at a drop of but 12.9 in. This 
gear, therefore, which is of the identical 
capacity as the 3^ in. travel gear, will 
shear the rivets at 12.9 in. drop, whereas 
the 3% in. travel gear will require 34.2 in. 
drop. This increase in drop is due solelv 
to the increased travel of the gear with con- 
sequent decrease in ultimate resistance. At 



the bottom of Fig. 41 are shown superim- 
posed diagrams of two gears, each of 2y 2 
in. travel, but the one of 26.2 in. drop capa- 
city and the other 39.3 in. drop capacity, 
or just 50 per cent increase. In the case of 
the lighter capacity gear the rivets do not 
shear until the gear goes solid or at 26.2 in. 
fall. In the case of the larger capacity 
gear the rivets would shear at 17.6 in. drop. 
Here is shown how by simply increasing 
the capacity of the gear 50 per cent the y 2 
in. rivets are caused to shear 13.1 in. lower 
than with the lighter capacity gear. These 
conditions are for straight line gears and 
for shearing the rivets at a single blow. 
When a succession of blows is given from 
varying heights the difference becomes 
even more marked, as a heavier capacity 
gear begins to punish and permanently de- 
form the light rivets early in the test. 

The above principles are reflected in the 
test results. Thus the Sessions K gear and 
the Cardwell G-25-A were of practically 
equal drop test capacity but different 
travels, namely, 2 T X g in. and 2% in. re- 
spectively. The Sessions K gear (2-fa in. 
travel) sheared the rivets at 12.5 in., while 
the Cardwell (2% in. travel) sheared them 
at 22.8 in. Again, the National H-l gear 
sheared the rivets at 10 in. fall, while the 
National M-l gear sheared them at 19.5 in. 
fall. Here the travels of the gears are the 
same, but one gear had a drop test capacity 
of 32.5 in., while the other had 18.5 in. 

An effort was also made to test all the 
gears on full-sized rivets, a total of twenty- 
four % in. rivets (16.57 sq. in.) being used 
for the two lugs. It was hoped that by 
using full-sized rivets an idea could be ob- 
tained as to the relative merits of the gears, 
based upon the shearing point or upon the 
destruction of the gear prior to shearing. 
Three types only were attempted on these 
rivets, as in each instance the gears failed 
before shearing occurred. Further * tests 



Draft Gear Tests of the U. S. Railroad Administration 

P/VET VALUE /89O0O* 



11 



/89,000** 




/3300O* /9/VET VALUE 




/89.000* 




V„///////////////,/,,///////////,////////,//////////,„s>. 



„„/,,„///* /,///„/////,//. 



/.€7' 



2.S0' 



Fig. 41 — Diagrams of Rivet Shearing Action of Draft Gears 



78 



Draft Gear Tests of the U. S. Railroad Administration 



were prevented by breaking of the set-up, 
but this limited experience showed the fu- 
tility of attempting to use full-sized rivets 
for testing all gears. From this experience 
and from careful study, it is believed the 
present y% in. rivet shearing test is not a 
fair method of grading gears. Car sills are 
designed for a load of 500,000 lb. and it 
therefore should not be expected to hold 
the draft gear to the limits required by this 
light test. It is believed possible, however, 
to develop a rivet shear test to grade gears 
of all capacities, and investigations have 
been outlined to develop a test of this char- 
acter. In this work the following points 
will be established or disproved: 

1. That rivet shearing tests should be 
designed to show smoothness of action and 
the ultimate dynamic resistance of the 
gears. 

2. That such tests should not be carried 
beyond the solid point of the gear, because 
of the fact that all gears are not of equal 
rigidity when solid. 

3. That the rivets should be of such area 
that a single blow may be given from a 
stated height, within the capacity of the 
gear, and the rivets not be sheared. 

4. That the rivets should shear at a blow 
from not more than a stated height above 



the solid point; this in order to penalize 
over-solid weakness of construction. 

5. That the tup should not be dropped 
through successive heights increasing by 
1 in. increments because of passing the 
elastic shearing limit of the rivets before 
the gear is solid, but that the gear should 
be set up on lugs or the equivalent and a 
single blow given from a specified height 
for that particular gear and the rivets not 
be sheared. Using a new set of lugs, an- 
other single blow should be given from a 
second specified height at which the rivets 
should shear. 

6. That the number of rivets used and 
the heights of drop should not be the same 
for all gears but should be set for each type 
in accordance with its capacity and travel. 

7. That the rivet area and height of fall 
should be determined by the drop test ca- 
pacity and travel of the gear. 

8. That the test rivets should be of high 
carbon steel or other material having a 
high elastic shearing limit; this in order 
to avoid the uncertainty of the exact shear- 
ing point. 

9. That when all gears are constructed 
of equal travel the question of rivet shear- 
ing tests will be greatly simplified. 



CAR-IMPACT TESTS 



In order to obtain an exact knowledge 
of the action of gears in service, car-impact 
tests were made, using the same gears as in 
the foregoing laboratory tests. The re- 
sults are therefore of especial interest as 
showing not only the action of the gears 
themselves under service conditions, but as 
demonstrating also, for the first time, how 
laboratory tests compare with service ac- 
tion. The gravity testing plant of the T. H. 
Symington Company at Rochester, N. Y., 
was used for these tests. In general, the 
use of private laboratories of interested 
companies was avoided, the preference be- 
ing given to the testing facilities of rail- 
roads. This being the only plant of its 
kind in existence, however, and the Sym- 
ington Company being interested in the 
manufacture of draft gear attachments 
rather than of gears, and having no gear 
in the tests, the Section availed itself of 
the opportunity to use the Symington test- 
ing facilities. 

This plant was originally built for in- 
vestigating the action of full-sized cars, 
either loaded or empty, when equipped 
with different draft gears. The Symington 
Company, who were practically pioneers 
in this work, constructed the plant with the 
prime idea of studying the action of the 
cars when equipped with different gears 
rather than investigating the action of the 
gear itself. As originally constructed and 
used, much valuable information was ob- 
tainable from this equipment although, as 
in any other impact testing, misleading con- 
clusions as to the relative merits of draft 
gears could be unintentionally reached by 
subjecting gears to oversolid car veloci- 
ties. The extended remarks heretofore 
made regarding over-solid laboratory test- 



ing apply equally as well to this service 
testing. Over-solid testing should never be 
done except for discovering weak gear con- 
struction. Some of the earlier tests have 
been of value, however, in showing what 
slightly over-solid speeds are necessary to 
produce gear injury and failure. After the 
owners had made certain changes and ad- 
ditions desired by the Section for a more 
exact investigation of both gear action and 
car action, at speeds within the ranges of 
the gears, the Symington plant was taken 
over and operated by the United States 
Railroad Administration for the purpose 
of the car-impact tests. 

The Symington Test Plant 

In general this test plant consists of a 
test track with two full-sized cars which 
can be caused to collide at any desired 
velocity, accurate means being provided to 
record the results. The first portion of 
the track is inclined in' order to impart 
velocity to one of the cars. This section 
of track is 147 feet in length and is on a 
general grade of 12 per cent. An electric 
hoist is located in a small house at the top 
of the incline and this hoist through the 
medium of a puller car, is capable of draw- 
ing a loaded 50-ton car up the incline. At 
the foot of the incline is a 53 ft. section of 
approximately level track which terminates 
in a 196 ft. section of track on a 1 per 
cent ascending grade, this in turn termi- 
nating in a 287 ft. section of track on a 
iy 2 per cent grade. The entire test track 
is thus 683 feet in length, beginning on a 
12 per cent descending grade and ending 
on a iy 2 per cent ascending grade. The 
track is straight throughout its length. 



79 



80 



Draft Gear Tests of the U. S. Railroad Administration 




Draft Gear Tests of the U. S. Railroad Administration 



81 




Qhj— 



&bO 



8$ 



|5 
S6> 



#3TVto- 



%\ 



A 



xw/si/cu 



m 



Two composite gondola cars of 50 tons 
capacity are used, one of which, termed 
for reference car "B," is spotted at a cer- 
tain point at the beginning of the 1 per 
cent grade. The other car, termed car 
"A," is drawn up the incline by means of 
the puller car and hoist. A movable trip 
block is clamped on a third rail located 
alongside the track. The puller car has a 
projecting trip-lever which strikes the trip 
block, releasing car "A" and allowing it 
to roll down the incline. When fully on 
the level portion of the track, car "A" col- 
lides with the standing car "B." Either 
or both cars may be equipped with draft 
gears of any type, and both cars are free 
to follow such movement during and after 
the draft gear cycle as -may result from 
the use of the particular gear. A general 
photographic view of this test plant is 
shown in Fig. 42. 

Fig. 43 shows the general profile of the 
test track with the test cars in positions as 
at the first instant of impact. While the 
general condition of the track is good, any 
local variations in elevation would influ- 
ence the results of the tests unless con- 
sidered in the calculations.' Accordingly 
a minute check of the critical portion of 
the track was made, the levels being taken 
while moving the loaded cars over the 
track. Fig. 44 shows in magnified scale 
the true path of the center of gravity of 
one of the test cars as it moves along the 
portion of the track traversed by the cars 
during the tests. Figs. 45 and 46 show to 
a still greater magnification the exact paths 
of the centers of gravity of the two cars 
over the short portions of the track trav- 
ersed during the draft gear cycle. With 
the aid of these profiles, Figs. 44 to 46, it 
is possible to make a careful and exact 
study of the energy transferrence from one 
car to the other, and of that absorbed by 
the draft gears and cars. 

The test cars are 50-ton low side, com- 
posite gondolas, 46 ft. in. inside length 
with fish-belly center and side, sills and 



82 



Draft Gear Tests of the U. S. Railroad Administration 



with a steel frame superstructure. The 
cars have 214 in. floor planking and S 1 /^ 
in. side and end planking. Each of the 
cars has four diagonal floor braces of 5 in. 
channels at the corners, and each has been 
supplied in addition with four diagonal 
braces at the center, extending from the side 
sills to the center sill, these latter braces 



The test cars are equipped with Farlow 
Two-Key draft gear attachments as shown 
in the photographic reproduction, Fig. 48, 
and the test gears may thus be carefully 
adjusted in the draft gear pocket. In this 
arrangement the gear is positioned between 
the arms of the horizontal wrought steel 
yoke. In buffing, the gear seats against the 



/ 



Prof//e defined ny center of 
growfy of a fesf car mov/na 
a/on6 test track. \ 



tior/zonfat Scotef"=8ft 
Verf/caf Seated W ft: 




/O /5 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 35 ZOO /05 //0 

Cor Movement — Feet 
Fig. 44 — Enlarged Profile of Test Track for 90 Feet 



being 6 in. by 4 in. by % in. angles. The 
light weight of each car is 47,800 lb., and 
they have been loaded with pig iron to give 
a total gross load of 143,000 lb. per car. 
Wood cribbing is arranged inside of the 
car to hold the lading against shifting. A 
general view of one of these cars (car B) 
with its lading is shown in Fig. 47. These 
cars were reweighed and the lading prop- 
erly adjusted and distributed before be- 
ginning the tests. Care was taken to avoid 
testing after heavy rainstorms, as it was 
found that each car took up approximately 
1,200 lb. of water during a prolonged rain. 
The brakes were removed from the cars to 
avoid any possibility of dragging shoes. 



rear follower, which latter bears against 
the rear of the yoke. The yoke in turn seats 
against the cast steel back-stop and bolster 
center casting. This casting bridges be- 
tween the sills and ties them together, there 
being a total of seventy-four % in. rivets 
supplied for transferring the buffing force 
from the backstop casting to the center 
sills in each of the test cars. The draft 
gear is held to compressed position by 
means of the second draft key, which in 
service forms also the front pulling stop 
for the gear. The regular practice in this 
form of attachment is to have this key 
protect the draft gear by allowing it to 
strike the ends of the slots in the check 



Draft Gear Tests of the U. S. Railroad Administration 



83 



plates and sills at the same time the gear 
goes solid. In the tests, however, the slots 
were lengthened at the rear to prevent this 
key ever going solid. 

A dummy coupler having a flat buffing 
face and of 16 sq. in. cross sectional area, 
was used instead of a standard coupler. 



The artificial looseness or slack resulting 
between the coupler butt and the front fol- 
lower was taken up by temporary wedges 
before each run so that all action, both on 
compression and release, could be re- 
stricted to the gears themselves and be 
definitely measured and recorded. 



f2 



08 



04 



Defait Faff? of center of gravity 
of Cor A during impact 
fiorizontot 5co/e ■/"=/" 



Verticat Scafar=j£>ft 



i 

53 



~-T/?/$ tine corresponds 
w/in Station 20 on D/agrdm 
figure 23. 



234-56735/0 
Cor Movement 1 — /ncfyer 

Fig. 45 — Enlarged Profile for 12-in. Movement of Car A 



// 



/2 



276 



212 



2.68 



5P 



Detaii Path of center of gravity 
of Cor 3 daring impact 
ftonzonfat Scaie-t '"=/"_ 
Vert/cat 3cate-f'= / t ft 



264 



* — This //ne corresponds 
with STo. 70 on Diagram 
F/gure 29. 



260 



Fig. 46- 



3 4 3 6 7 8 3 

Cor Movement— inches 

-Enlarged Profile for 12-in. Movement of Car 



/O 



// 



/2 



The front key, which passes through the 
key slot of this coupler and through the 
front slots in the yoke, was used in these 
tests for supporting and aligning the parts 
only. The front end of the dummy coup- 
ler shank was guided both vertically and 
laterally. In all tests care was taken to see 
that the draft gears seated against the sec- 
ond key and not against the coupler key. 



Action of Cars During Impact 

In any case of car-impact, the first and 
prime effort is for the velocities of the two 
cars to equalize; that is, for car A to slow 
down and car B to speed up. This is 
caused by the effort of car A to push car 
B ahead, which continues as long as the 
velocity of car A is greater than that of 



84 Draft Gear Tests of the U. S. Railroad Administration 




Fig. 47— General View of Car B and Its Lading 



Draft Gear Tests of the U. S. Railroad Administration 



85 



car B. This pushing or propelling effort 
must always result in the compression or 
yield of some part or parts of the car. The 
draft gears are supplied for the purpose 
of providing this yield and to reduce the 
amount of yield required from the car 
structure. But in every case of impact, 



plished by certain forces working through 
a certain space represented by the addi- 
tional yield of the solid parts, the force 
going directly through the housing to the 
sills. The couplers, gear housing, and sills 
must now continue to yield until the car 
velocities are finally equalized. The amount 




Fig. 48— Farlow Two-Key Draft Gear Attachments Used on Test Cars 



some part or parts of the cars, either draft 
gears or other more rigid car parts, will 
continue to compress or yield until the very 
instant when the velocities are equal. For 
light impacts, the velocities are usually 
equalized without compressing the draft 
gears to their full amount. In the case of 
an over-solid velocity, the draft gears will 
first be fully compressed, their resistance 
slowing down car A and speeding up car 
B. But in this over-solid case, when the 
gears are fully compressed, car A has still 
a greater velocity than car B and it will be 
apparent that car A will continue to urge 
car B forward. This results in an impact 
directly upon the gear housing. The ad- 
ditional work to be done must be accom- 



of yield and the magnitude of the forces 
are inversely proportional and depend en- 
tirely upon the sturdiness of, or the re- 
sistance offered by, the parts. The sturdier 
the parts, the more force will be required 
to deform them and the less will be the 
amount of penetration and yield and in- 
cidentally the lower will be the unit stress. 
On the other hand, the lighter the parts 
the greater will be the yield and the less 
the force, but the higher will be the unit 
stresses. Accordingly, although providing 
a temporary cushioning for the over-solid 
blow, the lighter parts will shortly be de- 
formed or broken. Any weak link, be it 
coupler shank, draft gear housing, draft 
lugs or center sills, will reduce the force 



86 



Draft Gear Tests of the U. S. Railroad Administration 



peak but only at the expense of its life. 

The velocity of car A is thus being 
gradually decreased and that of car B in- 
creased until the velocities are equal, at 
which instant all parts have reached the 
maximum of compression. If all of the 
parts were perfectly inelastic, if in other 
words, there should be no tendency for the 
gears to release themselves or for the car 
structures to give back the energy of their 
elastic yield, it is evident that there would 
then be no force of recoil to separate the 
cars, and both cars would accordingly 
move off together at this equal velocity, 
each car having one-half of the original 
velocity of car A, neglecting a slight loss 
due to internal resistances. With equal 
rolling and grade resistance, the cars 
would continue together until both finally 
came to rest without separation. Except 
for the slight loss due to rolling resistance, 
the work done in compressing the gears 
and car structure is thus always equal to 
one-half of the original kinetic energy in 
car A, and it should be especially noted 
that this is the same whether there be no re- 
coil of the gears and car parts, or full re- 
coil. 

The force exerted between the cars in 
compressing the gears and car structure is 
entirely independent of the question of ab- 
sorption. Up to the point of maximum 
compression the matter of absorption of 
energy has not entered into or influenced 
the problem. It is entirely a question of 
force and yield and it should be remem- 
bered that frictional resistance, while truly 
absorbing energy (foot-pounds) does not 
in any manner whatsoever reduce or "ab- 
sorb" force. The force required to close 
a friction draft gear, and consequently the 
force going through the gear to the sills, 
may be greater or less than a spring draft 
gear of equal capacity, depending solely 
upon its compression curve, and not in 
the slightest degree upon its percentage of 



absorption. The cushioning value of a gear 
therefore is not measured by absence of re- 
coil, or energy absorption, but solely by 
its action during the closing period. 
Whether or not a gear has extensive recoil 
has nothing to do with its action on com- 
pression, or with the force delivered by the 
gear to the car during its compression. 

In practice, the cars having reached a 
point in the draft gear cycle where their 
velocities are equal, and the compression 
period of the cycle completed, the re- 
lease of the gears begins. All gears have 
more or less recoil and it is this force, 
together with the rebound of the car struc- 
ture, that tends to part the cars and to cause 
one car to travel faster and farther than 
the other. It should be especially noted that 
the force of recoil has the same effect be- 
tween the cars as the force of compression; 
namely, to reduce the velocity of car A and 
to increase the velocity of car B. During 
the period of gear compression the force 
between the cars, or the force tending to 
accelerate car B, results from the higher 
velocity of car A, or its direct tendency 
to push car B ahead. During the period of 
draft gear release, the force tending to 
further accelerate car B or to urge it 
forward, results from the recoil or return 
of stored energy in the two draft gears and 
both car structures. 

The recoil of the gears and car parts 
thus giving to car B a greater velocity and 
to car A a lesser velocity, car B will begin 
to travel faster than car A, and the gears, 
following the resulting parting of the cars, 
will continue to release until final separa- 
tion of the cars. It is evident that the 
greater the force of recoil, or release, the 
greater the pressure between the cars dur- 
ing release, and consequently the higher 
will be the velocity attained by car B and 
the greater the retardation of car A. A 
gear with 100 per cent recoil would ac- 
tually bring car A to rest by the time the 



Draft Gear Tests of the U. S. Railroad Administration 



87 



cars separate, while car B would be pushed 
ahead at a velocity practically equal to the 
original impact velocity of car A. On the 
other hand, a gear with no recoil, or 100 
per cent absorption, would, as heretofore 
set forth, cause both cars to move off to- 
gether, each at one-half the initial velocity 
of car A. Gear absorption is thus inversely 
proportional to the pressure exerted be- 
tween the cars during the period of release, 
the effect of high absorption being to hold 
the two cars at nearly equal velocities after 
impact. This means, in effect, that with 
high absorption of energy, car B will not 
be propelled at so high a velocity and con- 
sequently will strike the next succeeding 
car at a reduced velocity, while with no 
absorption, car B will strike the next car 
at almost the same velocity as the original 
of car A. Absorption therefore is not 
primarily a means of reducing the force of 
impact between the first two cars, or of 
protecting these cars, but is a means of re- 
ducing the moments of the successive im- 
pacts between successive cars in a train. 

The following may be acepted as general 
principles of draft gear action in impact: 

1. That draft gears are compressed only 
because of differences of velocity between 
adjacent cars. 

2. That the resistance offered by the gear 
during compression tends to overcome the 
difference of velocity of the cars and tends 
to bring both cars to the same velocity. 

3. That gears continue to close, and at 
over-solid velocities the car structures con- 
tinued to compress, until the car velocities 
are equalized. 

4. That this action of a gear is inde- 
pendent of its ability to absorb energy, or 
in other words, is the same whether- the re- 
sistance be obtained from friction or solely 
from spring action. 

5. That the cushioning offered by the 
compression of a draft gear is not depend- 
ent upon its percentage of absorption. 



6. That absorption does not in any man- 
ner reduce the force going through the 
draft gear to the car sills while the gear is 
being compressed, and does not lower the 
force exerted betwen the first two cars col- 
liding. That it does act to lower the ve- 
locity with which the second car strikes the 
third car and consequently reduces the 
force between successive cars. 

7. That the amount of "work-absorbed" 
by a gear, or the percentage of absorption 
does not regulate or reduce the force of 
first collision, but is important as deter- 
mining whether shocks will run practically 
undiminished throughout the train or 
whether there will be successive reductions 
in their moments from car to car. 

8. That the first measure of a draft gear 
is the amount of energy required to close 
the gear, this being the sole factor from 
which to determine for what switching 
speeds a gear is suitable. This is ex- 
pressed as "work-done" and has no rela- 
tion whatsoever to "work-absorbed." 

9. That the next requirement is that a 
gear, either spring or friction, shall com- 
press with such a rate of' increase of re- 
sistance as will cause the lowest practical 
ultimate force and the least practical vibra- 
tion of the car structure. 

10. That the next measure is with respect 
to the action of the gear on release or the 
amount of the recoil, whether the energy of 
compression is returned, to go on to the 
next car, or whether it is partially absorbed 
as by friction. This property is expressed 
by the term "work-absorbed." 

Records in Car-Impact Tests 

In the car-impact tests the following 
records were taken: 

Impact velocity of car A. 
Travel of cars along track. 
Draft gear travel and action. 
Seismograph readings. 
Graphs of car action. 



88 



Draft Gear Tests of the U. S. Railroad Administration 



From these prime records a complete 
study of the action of both the gears and 
cars can be made, the details of which will 
appear as the manner of making and in- 
terpreting the several records is discussed. 

Impact Velocity 

The first information needed in such 
tests is an accurate knowledge of the vel- 
ocity of car A at the very instant of im- 
pact. It is not enough to simply release 
the car at a fixed point along the incline, 
for the same station will not always de- 
velop the same velocity. Nor is it satis- 
factory to establish five-foot or ten-foot 
stations near the point of impact and cal- 
culate the impact velocity by means of the 
average velocity between these stations, as 
very marked changes in velocity may oc- 
cur over such periods. The kinetic energy 
of car A is determined from the impact 
velocity, and as it varies with the square of 
the velocity, and furthermore as all of the 
results of the tests are based upon this rec- 
ord, accuracy here is of utmost importance. 
In these tests car A was caused to draw a 
velocity line upon a revolving drum, so 
that the exact velocity at the very instant 
of impact is obtained within a possible er- 
ror of less than 1 per cent. A more de- 
tailed description of the recording device 
will be given later under the heading of 
"Car-Movement Curves." 

Travel of Cars Along Track 

An interesting record, easily obtainable, 
is the distance each of the two cars travels 
along the track after the impact. Care 
must be taken in interpreting these figures, 
however, as a slight change in grade wilj 
offset a considerable track movement of 
the cars. Thus, if but one of the eight 
wheels of a car mounts an obstacle on the 
track -fa in. in height, it is equivalent to 
six inches additional movement of the en- 
tire car along level track. An interesting 



point in connection with this record is 
that for equal impact velocities, the higher 
the recoil of the gear used, the greater the 
distance car B will travel. In general, the 
recoil of gears will be proportional to the 
distance between the cars after coming to 
rest; that is, the greater the recoil the 
farther apart will be the cars when they 
come to rest. 

Draft Gear Travel and Action 

Knowing the impact velocity, the next 
point of interest is the amount of and 
the nature of the travel or yield of the draft 
gears. The test cars are equipped with fric- 
tion plunger gages to show the amount of 
coupler travel. This corresponds reason- 
ably closely with the actual draft gear 
travel, but is not sufficiently accurate for 
analytical investigations. In order to obtain 
a more direct knowledge of the movement 
and action of the gears, car B is provided 
with a small revolving drum upon which 
is drawn a curve which shows not only 
the amount of draft gear movement for that 
car but the character of the movement; 
that is, whether the gear compresses and 
releases regularly or irregularly. A pho- 
tographic view of this instrument is shown 
in Fig. 49, a case or bracket being secured 
to the side sill of car B in which is a small 
motor-driven drum which extends trans- 
versely of the car. A pencil is caused to 
move lengthwise of the drum in harmony 
with the movement of the front draft gear 
follower. For this purpose a piano wire 
extends from this draft gear follower to the 
pencil arm, the connections being arranged 
in such manner that tipping of the follower 
block will not produce false movement of 
the pencil. Relative movement between 
the side sill and the center sill is also com- 
pensated for. A 40 lb. coil spring and a 
40 lb. friction drag prevent overtravel of 
the pencil, the spring alone serving to re- 
turn the pencil during the release of the 



Draft Gear Tests of the U. S. Railroad Administration 



89 



gear. The drum is covered with paper, and 
as the gear is compressed or released the 
pencil is moved correspondingly along the 
axis of the revolving drum, thus producing 
a time-closure diagram for the gear in 
car B. 

Tests were in each instance made with 
gears in both cars and again with a gear 



regularly, others, particularly those from 
friction gears of high capacity, are often 
closed by a succession of alternating move- 
ments or jerks. This will be shown as the 
individual cards are reproduced. The 
lower capacity gears naturally show 
smoother gear action than those of higher 
capacity. In fact, without exception, the 




.15 .Bo 

TTme- Seconds 
_25g SEC. gEAR cycle 



.30 



Fig. 50 — Specimen Time-Closure Curve Produced on Small Drum of Car B 



in car B only, car A in the latter case being 
fitted up with a solid steel block instead of 
a draft gear. The action of the individual 
gear can be best studied under these latter 
conditions because it is definitely known 
that any irregularities recorded are due to 
the particular gear. In the former case the 
record does not determine which of the two 
opposing gears is responsible for the ir- 
regularities. Such irregular action is al- 
most invariably recorded when both cars 
are equipped with gears. The specimen 
card reproduced in Fig. 50 was made 
from the gear in car B when each car was 
equipped with a friction draft gear. This 
card shows the typical action of friction 
gears in the double-gear tests, or when 
both cars are equipped with gears. 

By means of these cards it is found that 
while some draft gears act smoothly and 



high capacity gears show jerks and irregu- 
larities in the compression line of the 
time-closure diagrams. This, in the single 
gear tests, is believed to be due largely to 
the pulsations or periodic vibrations be- 
tween the two cars resulting from the high 
forces incident to a high capacity gear with 
short travel. The cards show that with a 
gear in each car, the two gears do not work 
in harmony; that frequently on compres- 
sion, and almost invariably on the release, 
one gear will work for a while and then 
the other one will operate. From this it is 
concluded that twin arrangement of fric- 
tion draft gears is 1 not permissible. 

Seismograph Readings 

Each of the test cars is equipped with a 
pendulum device, secured to the side of 
the car, and so arranged that the retarda- 



90 Draft Gear Tests of the U. S. Railroad Administration 




Fie. 49 — Instrument on Car B for Recording Draft Gear Action 



Draft Gear Tests of the U. S. Railroad Administration 



91 




Fig. 51 — Seismocraph of Car A 

tion or acceleration of the cars will cause 
the pendulums to swing upward by virtue 
of the inertia of their own masses. Gradu- 
ated quadrants are arranged as guides for 
the pendulum weights, and a light friction 
runner is carried with the weight and is 
left standing upon the guide at the highest 
point reached by the pendulum. The 
graduations are proportional to the verti- 
cal lift of the pendulum. Thus when the 
registration is 4.0 the pendulum has 
reached a vertical displacement twice as 
great as when the registration is 2.0. A 
photographic reproduction of the seismo- 
graph of car A is shown in Fig. 51. The 
seismograph records are usually attractive 
to the observer but are not of great im- 
portance in the study of gears. This is 
due primarily to the fact that the sides of 
the car have some movement with respect 
to the center of the entire mass. The quick 
vibrations of the side of the car appear 
also to influence the seismograph readings. 
These instruments are frequently spoken of 
as "shift gages." 



Graphs of Car Action 

As the final study of draft gear action 
must lie in a study of the results of the 
use of the gear upon the car and its lading, 
arrangements were made to obtain a com-' 
plete and accurate record of the perform- 
ance of both cars during the brief period 
of the draft cycle. A recording apparatus, 
arranged to draw simultaneous time-dis- 
placement curves of both cars, was de- 
signed and installed and a system of cer- 
tain reference lines worked out whereby 
these curves could be later so super-im- 
posed that at any instant during the draft 
gear cycle an exact knowledge of the per- 
formance of both cars could be had. These 
curves are commonly referred to as "car- 
movement curves." Photographic repro- 
ductions of the instruments for producing 
these curves are shown in Figs. 52 and 53. 
The apparatus has two drums mounted 
upon a common shaft and is placed on a 
stand alongside of the track. Each drum 
is 20.05 in. in circumference over the 
paper, and 30 in. long. The axis of the 
shaft is parallel to the track and the drums 
are so mounted upon the, shaft that one 
drum is alongside of the striking end of 
car A and the other alongside of the struck 
end of car B. Each drum has a pencil car- 
riage that is moved lengthwise of the drum 
by the movement of the car, each car hav- 
ing a pencil-propelling plunger attached 
to its side sill (see Figs. 49-52-53). Suit- 
able angle iron guides are arranged upon 
the instrument stand to cause the plungers 
to move into or out of engagement with 
he pencil carriages at the proper times. 

Making a Test Run 

In making a test the first operation is 
oroperly to apply the test gears to the cars. 
Care is taken to so adjust the length of the 
draft gear pockets that the gears will be 
held to their proper lengths. It is some- 



92 Draft Gear Tests of the U. S. Railroad Administration 




u 



— — 



Draft Gear Tests of the U. S. Railroad Administration 93 




Fig. 53 — Another View of Instrument for Recording Car Action 



94 



Draft Gear Tests of the U. S. Railroad Administration 



times necessary to apply liners behind the 
gear in order to accomplish this. After 
applying the gears to the cars, it is the 
practice to make ten preliminary runs at 
just slightly below the dosing speed, in 
order to condition the gears before mak- 
ing the regular runs. Car B is then spotted, 
always at the same definite station along 
the track. Car A is also spotted, the buffing 
faces of the couplers being just in contact 
and all loose slack being eliminated or 
compensated for. With the cars so spotted 
and with the A and B pencils in positions 
on their respective drums corresponding 
with the positions of cars A and B re- 
spectively, the drums are rotated a few 
times, thereby drawing the datum lines, 
A- A for car A, and B-B for car B (see 
Figs. 54 and 55). At the same time the 
small drum is rotated a few times so that its 
pencil draws the datum lines for this rec- 
ord (see Fig. 50) . It will thus be seen 
that all of the datum lines are drawn with 
the cars and gears in position as at the first 
instant of impact; or, in other words, at the 
beginning of a true gear compression. Ac- 
cordingly, in comparing the cards, it is 
definitely known that all car movements 
and gear action can be compared from 
these common datum lines. 

Without rotating the drums, each of the 
pencils is given a slight longitudinal move- 
ment, in order to draw the reference lines 
D-D and E-E on the A and B cards re- 
spectively (see Figs. 54 and 55). The 
pencil for car B is left standing exactly 
upon the datum lines B-B, or in other 
words, in position so that the first move- 
ment of car B will move this pencil along 
drum B. Car A is then drawn away from 
car B and the pencil for car A is drawn 
along the axis of drum A in order that the 
approaching car A may propel this pencil 
for some distance before the pencil reaches 
the datum line A-A, or the position where 
the two cars first meet. By this means the 



exact impact velocity of car A is de- 
termined, the speed of rotation of the drums 
being known. In order to obtain as nearly 
as possible the desired velocity, "the trip 
is set at a prescribed point along the in- 
clined portion of the track. The velocity 
developed from any station varies from 
time to time, hence, the exact velocity of 
impact must be determined for each run 
from the line drawn by car A below the 
datum line A-A. As car A approaches 
car B, all of the drums are set in motion, 
care being taken to start the instruments 
a sufficient time in advance to get the drums 
up to constant speed before the pencils are 
moved. 

In the record from drum A reproduced 
in Fig. 54 the pencil was stationed at a posi- 
tion represented by the line F-F, until the 
approaching car picked up the pencil and 
began to propel it along the axis of the 
drum. The angular line drawn by the 
pencil between the lines F-F and A-A de- 
notes the velocity of car A, the paper speed 
being known. This line being straight 
shows that the drums rotated at a constant 
speed. From the preliminary set-up of the 
cars and instruments it is known that when 
pencil A reaches the position of the line 
A-A on this drum, the cars have just met, 
for as previously explained, the datum line 
A-A was established prior to the tests for 
indicating the position of this pencil along 
the drum at the first instant of impact. As 
car A propels the pencil beyond the line 
A-A it is known that the draft gear cycle has 
begun, and from the convexity of the curve 
it can be seen that the velocity of car A is 
being reduced, due to the resistance of the 
gears. 

At the instant when the cars first met, or 
when this car-movement curve crosses the 
datum line A-A, it will be seen that the 
pencil was 3% in. from the reference line 
D-D. It is known that at this instant the 
B pencil was exactly the same distance 



Draft Gear Tests of the U. S. Railroad Administration 95 



"* Q 

REFERENCE 
LINF — 

A 


=*'" » 






3 2 


X pDATi/M Line A 


a 
F / 


/ ^-CARS MET 
X D 

x u 

X > 

x o 

/ .2 

x of 

x < 

x u 

F 


x Paper Traveled 
34.1 "per Sec. 



Fig. 54 — Specimen Car-Movement Card from Drum A 





- 



































U 

i 
























h 
? 








U 




in 

DC 
< 







B 








^*>"*' ^-Datum Line 


B 


REFERENCE 
LINE "• 

M 








^ Paper traveled 
34.1" per Sec. 


J 2 





Fig. 55 — Specimen Car-Movement Card from Drum B 



96 



Draft Gear Tests of the U. S. Railroad Administration 



from its reference line E-E, for these refer- 
ence lines were previously drawn to denote 
the relative positions of the two pencils or 
the datum lines. It will be noted from 
card B, Fig. 55, that a small interval of 
time elapsed before car B began to move 
out of its spotted position, the gears in the 
meanwhile compressing. When it began 
to move, its velocity gradually increased 
as shown by the concavity of the curve. 

By means of the datum and reference 
lines on these two cards a system of super- 
imposition of the two curves has been de- 
veloped and in Fig. 56 these curves have 
been so superimposed. This is done by 
matching up both the datum and reference 
lines and tracing one curve upon the other. 
The exact meeting point of the cars is thus 
established for both curves and both are 
also synchronized as to time. Consequently 
both the velocity of the cars and their rela- 
tive positions can be determined for any 
instant. And at any instant, also, the dis- 
tance either car has moved from its spotted 
positions is known. It will be seen that car 
A, during the first portion of the draft gear 
cycle continued to travel at a higher vel- 
ocity than car B. As car A thus encroaches 
upon car B the draft gears are compressed, 
the distance betwen the two super-imposed 
curves representing draft gear compression, 
together with the slight yield of the car 
bodies. Car A continued to run down upon 
car B, its velocity gradually decreasing and 
the velocity of car B gradually increasing 
due to the draft gear forces exerted be- 
tween the cars, until both cars were of 
equal velocity. This point corresponds 
with the point of maximum draft gear com- 
pression and can be readily determined by 
finding the maximum ordinate between the 
two curves. From this point on, the ve- 
locity of car B becomes greater than that of 
car A due to the forces of draft gear re- 
coil between the cars. Consquently, car 
B moves away from car A, allowing the 



draft gears to continue their release. At 
the point where the two curves cross there 
is no relative displacement of the two cars, 
or in other words, each car has travelled 
the same distance from its datum line, and 
it is therefore definitely known that at this 
instant the cars parted and that the draft 
gear cycle was completed. 

From the superimposed curves, Fig. 56, 
it is possible to obtain a wide range of in- 
formation concerning car action and draft 
gear action. The dotted line erected upon 
the datum line, for example, shows the 
movement of the two draft gears during 
compression and release. This curve is 
obtained by the simple process of stepping 
off the ordinates between the two curves 
upon the datum line as a base. The point 
where this draft gear curve reaches its 
maximum height is the point of maximum 
draft gear compression, and a vertical line 
has been drawn to indicate this point on 
the curves. From this it is then seen that 
the period of draft gear compression was 
0.090 seconds and the period of release 
0.166 seconds, the entire draft gear cycle, 
or the total length of time the cars were 
in contact being 0.256 seconds. 

At the instant of maximum draft gear 
compression, car A had moved 2.52 in. 
along the track from the point of impact* 
while car B had moved but 0.42 in., car A 
thus having encroached upon car B for 
2.10 in., causing a corresponding amount 
of gear closure. At this instant, car A 
ceased encroaching upon car B, as shown 
by the falling off in gear closure. At the 
instant of maximum gear closure the ve- 
locities of the cars were equal, and the 
lines established tangential to the car-move- 
ment curves at this point denote the com- 
mon velocity at this instant. These tangen- 
tial lines also indicate the paths of the car- 
movement curves had there been no force 
of recoil, or if the draft gears had stuck. 
Angles have been drawn in to indicate the 



Draft Gear Tests of the U. S. Railroad Administration 



97 




98 



Draft Gear Tests of the U. S. Railroad Administration 



influence of gear compression and gear re- 
lease, and the dimension of 4.25 in. shows 
the track movement of the cars during the 
entire draft gear cycle. 

The card of Fig. 50 was drawn by the 
action of the draft gear in car B during 
this same run. It will be seen that this gear 
closed 1.06 in., thus showing that the gear 
in car A closed 1.04 in. While the line 
in Fig. 56, representing the sum of the ac- 
tions of the two gears is smooth and regu- 
lar, yet the individual gears did not operate 
so regularly. The compression and re- 
lease was attained by first one gear operat- 
ing and then the other. This is to be ex- 
pected from friction gears and indicates 
variations in the effective co-efficient of 
friction. No special demerit is attached 
to this action of a friction gear, as either 
one gear or the other is operating at all 
times. 

It is important to have an exact record of 
the paper speed and especially important 
that there shall be no variations in speed 
during a run. To this latter end, the elec- 
tric current for operating drums A and B 
was supplied by a set of twenty-four Edi- 
son batteries which were frequently re- 
charged, and as no other current was drawn 
from these cells the speed of the drums was 
kept practically constant. The speed, how- 
ever, was checked at frequent intervals to 
guard against errors in this respect. With 
a definite knowledge in each instance of 
the paper speed, it is possible to establish 
the time ordinates, and from this scale is 
deduced the time interval required to close 
the draft gears and the time interval for 
the release of the gears, the sum of these 
two intervals being designated throughout 
this report as the "draft gear cycle." The 
paper speed ranged around 34 in. per sec- 
ond throughout the tests, but the exact 
speed was known for each individual test. 
The time scale is, of course, necessary for 
determining car velocities, and from the 



superimposed curves it is a simple matter 
to determine the exact impact velocity of 
car A and also the exact velocities of both 
cars at the instant of parting. It is also 
possible to determine by tangents the 
change in velocity of each car during 
any period of draft gear compression 
or release. It is further possible to 
plot curves showing the instantaneous 
velocity of both cars, and from these it is 
a matter of simple calculation to produce 
curves showing the instantaneous energies 
in the two cars. From the rate of change 
of velocity, the mean or average forces 
working between the two cars throughout 
the period of impact may be computed and 
a continuous time-force curve plotted. 

By stepping off and plotting the vertical 
distances between the superimposed car- 
movement curves as heretofore explained, 
a time-closure curve of draft gear action 
can be produced. This curve will show the 
complete draft gear action, both compres- 
sion and release, plotted against time, and 
in cases where a gear is used in car B only, 
the curve will practically coincide with 
the curve drawn by the small drum on car 
B. This erected time-closure curve, how- 
ever, includes not only the yield of the 
draft gears but has added to this the yield 
of the two car bodies. In this connection, 
it should be remembered that any yield of 
the car body constitutes additional draft 
gear action. By combining the time-closure 
curve and the time-force curve, the time 
element being eliminated, there can be pro- 
duced a force-closure curve which corres- 
ponds with the ordinary static curve of 
draft gear testing, although produced from 
actual operation of the gear during impact. 

A large number of runs were made for 
each type of gear but the limitations of 
space and the labor of working them up 
in complete form do not permit the repro- 
duction of all of them in the report. The 
uniform practice has been followed of 



Draft Gear Tests of the U. S. Railroad Administration 



99 



working up and reproducing for each type 
of gear the following runs: 

1. A run, made at or near the closing 
point, with a calibrated test gear in car B 
only, car A being equipped with a solid 
steel block instead of a draft gear. 

2. A run made at approximately one 
mile per hour, each car being equipped 
with a calibrated test gear. 

3. A run made at or near the closing 
point, each car being equipped with a 
calibrated test gear. 

The first of these is worked up primarily 
that the action of a single calibrated gear 
in the car-impact tests may be compared 
with the action of the same gear in all of 
the laboratory tests, the possible influence 
of a second gear being removed. The sec- 
ond is worked up that a complete knowl- 
edge may be had of the action of each 
type of gear at low impact speeds. These 
low speed runs are especially useful in a 
study of train starting. The third is 
worked up as showing the best that may be 
expected from each type of gear at the 
maximum impact speed it is capable of 
cushioning, and gives the true comparison 
of the gears from the standpoint of yard 
service. 

The same gears of a type were used 
throughout the test, the general practice 
being to first make tests with both cars 
equipped, and then after replacing the gear 
in car A with the solid block, to make the 
single gear tests. 

Study of Curves 
A variety of interesting curves may be 
derived from the car-movement curves, but 
the essential features of the functioning 
of the gears will be shown in the following, 
which are reproduced for each of the three 
runs for each type of gear. 

Master Curves 
Car-Movement Curves — Superimposed. 



Derived Curves 

Velocity Curves. 
Energy Curves. 
Time-Force Curves. 
Time-Closure Curves. 
Force-Closure Curves. 

Throughout the report the curves have 
been reproduced to the same scale, so that 
the action of the different gears may be 
directly compared. The curves of the West- 
inghouse D-3 gear will be used for pur- 
poses of general description. 

Car-Movement Curves — Superimposed 

In tracing and reproducing the car-move- 
ment curves for publication it is not pos- 
sible to bring out all of the small variations 
and irregularities. In many instances these 
curves, although appearing smooth and reg- 
ular to the eye, contain numerous percepti- 
ble variations in the originals. All of the 
derived curves were produced directly 
from the originals and hence in the further 
studies of the gears the presence of any ir- 
regularities will be seen. The arms for 
producing the car-movement curves were 
attached to the side sills of the cars and al- 
though these test cars are equipped with 
two complete sets of diagonal braces, yet 
in severe buffing there is some movement 
of the side sill relative to the center sill 
and always more or less vibration. The ir- 
regularities in the car-movement curves are 
therefore due in a large measure to the vi- 
bration or to the relative movement of the 
side sills. The effect of these vibrations 
upon the car-movement curves, the full sig- 
nificance of which is brought out forcibly 
in the derived velocity curves, is probably 
the best comparative measure of the smooth- 
ness of action of the draft gears that can 
be obtained, for the smoother the action 
of the gear the more gradual and regular 
will be the transfer of energy from the 
striking car to the standing car and the less 



100 



Draft Gear Tests of the U. S. Railroad Administration 



will be the vibrations of the car structure. 
The superimposed car-movement curves, 
Fig. 80a, were made when car A was 
equipped with a solid steel buffer and car 
B with test gear No. 2. These curves rep- 
resent the closing run for a single West- 
inghouse type D-3 gear, the exact speed of 
impact being 2.68 M. P. H. At parting, 
car A had a speed of 0.74 M.P.H. and car 
B, 1.84 M.P.H. The instant of maximum 
gear compression, or in other words, the 
instant where the cars were of equal ve- 
locity, occurred 0.084 seconds after the 
first instant of impact. It required 0.166 
seconds for the draft gears to release, or 
for the cars to part. The duration of the 
entire draft gear cycle was 0.25 seconds. 
The combined draft gear closure and car 
body yield, which includes the movement 
of the side sills of the cars, amounted to 
2.65 in., this being the maximum ordinate 
between the two curves. At this instant 
car B had moved but 0.62 in. and car A, 
3.24 in. along the track. Incidentally, 
throughout these tests, it has been found 
that the draft gears are closed and the 
maximum force developed between the cars 
before car B moves any material distance. 
Each of the cars moved 5.07 in. along the 
track while in contact, or during the com- 
plete draft gear cycle. 

Velocity Curves 

Fig. 80d shows the derived velocity 
curves for the single gear run of the West- 
inghouse D-3 gear at the closing speed. 
The irregular dotted line shows the exact 
first derivatives of the car-movement curves, 
the first derivative being instantaneous ve- 
locities. Any slight irregularity in the 
car-movement curve becomes very appar- 
ent in this differentiation. The curves for 
the Westinghouse D-3 gears are unusually 
smooth for its capacity. 

The impact velocity of car A in this run 
was 3.93 feet per second (2.68 M.P.H.), 



the velocity of car B at this instant being 
zero. As the gears compressed, the ve- 
locity of car A decreased and the velocity 
of car B increased until at the instant of 
maximum gear compression both cars were 
of the same velocity, namely, 1.92 feet per 
second. The result of the closing of this 
gear, therefore, was to reduce the velocity 
of car A from 3.93 feet per second to 1.92 
feet per second. The remainder of the 
change in velocity of the two cars is due 
to the recoil of the gear, the effect of the 
recoil being to increase the velocity of car 
B to 2.69 feet per second and to still further 
reduce the velocity of car A to 1.08 feet 
per second at parting. 

The velocities represented by the irregu- 
lar dotted lines are true representations of 
the actual velocities of the side sills of the 
cars with respect to a stationary point along 
the track. It is not to be understood, how- 
ever, that the entire masses of the cars fol- 
lowed these velocity changes. Even though 
well constructed, these cars, like all others, 
are elastic and subject to more or less yield 
and vibration of parts. The irregularities 
in the velocity curves are accordingly due 
largely to the local surging and vibrations 
of the side sills. The frequency and am- 
plitude of the irregularities are a direct 
comparison of the results of the use of the 
various gears upon the cars. Thus it will 
be seen that with a spring draft gear, and 
with some of the lower capacity friction 
gears, the transfer of motion from one car 
to the other is effected with practically no 
disturbance of the car structure, the ve- 
locity curves being relatively smooth. On 
the other hand, with the higher capacity 
gears, considerable vibrations are set up. 
It is not to be expected that a gear func- 
tioning up to, say, 4 miles per hour, will 
give as smooth and regular a velocity curve 
at its closing speed as one functioning only 
to 2 miles per hour. The point of real in- 
terest is to compare the relative smoothness 



Draft Gear Tests of the U. S. Railroad Administration 



101 



of these curves from gears of the same ca- 
pacities and at approximately the same im- 
pact speed. 

It is not possible to obtain a true velocity 
record of an ordinary car from any one of 
its parts. Local vibrations and surges oc- 
cur in every particle of the car, even in 
the center sills. It would be possible to 
record the change in velocity of a car if it 
were constructed of a solid block, as of 
cast iron or cast steel, for in such a structure 
the vibrations would be so small as to be 
negligible. In such a test it should be pos- 
sible to determine draft gear resistance to a 
nicety. But because of the very fact that 
with a cast iron car vibrations and elastic 
yield are practically impossible, such an 
outfit is unfit for the test. Compressing a 
gear between two inelastic cars will not per- 
mit the development of the very things, 
viz., irregularity of gear action, that are 
being searched for. For if the structure, 
the inertia of which resists the compression 
of the gear, is incapable of yielding and 
vibrating, then the tendency of the gear to 
produce and to follow such vibrations in 
test action will be prevented, and any gear, 
unless of the most erratic nature, will pro- 
duce a smooth closure curve. This fact 
makes it imperative that draft gears should 
be tested upon actual cars so that if a gear 
has a tendency to pinch and bind on com- 
pression, it will be developed and dis- 
covered. 

It should be remembered that these car- 
body vibrations are a product of the in- 
dividual car and that each car will produce 
its own variations in velocity curves, due 
to the peculiarities of the particular car 
construction. Further, these vibrations in 
the velocity curves should not be inter- 
preted as meaning that the side sills of the 
cars vibrated through such distance. They 
represent instantaneous changes in velocity 
and the actual movement of the side sills 
that occurred were very slight; in many in- 



stances barely more than a tremble and 
seldom more than y% in. Mean velocity 
curves, shown in full lines, have been es- 
tablished from the general trend of the 
original car-movement curves, and these 
represent, as closely as it is practical to ob- 
tain, the true mean velocity of the entire 
mass of the car. This mean velocity curve 
is used throughout the remainder of the 
cards for the determination of energy and 
force. 

An interesting point in connection with 
the vibration of the cars was experienced 
when first developing the instruments at 
the Symington test plant. The first car- 
movement curves attempted were exceed- 
ingly irregular and showed a continuous 
series of waves, even when using spring 
draft gears at low impact speeds. These 
waves were found to be due to the longi- 
tudinal vibrations of the car body and 
truck bolsters upon the truck springs. 
Liners were applied between the truck bol- 
sters and the bolster guides of the truck 
side frames to prevent this vibratory move- 
ment upon the springs, but at the same time 
allowing vertical movement. The next suc- 
ceeding runs were smooth. ' It is recognized 
that in producing this artificial rigidity be- 
tween bolsters and side frames, the action 
of all the gears may have been very slightly 
smoothed out. For the surging of the body 
upon the truck springs might under some 
circumstances be reflected in the action of 
the gear. 

The production of the velocity curves 
from the car-movement curves, and espe- 
cially the showing of all the variations, was 
made possible by the use of a mechanical 
differentiating machine devised and built 
by Mr. Armin Elmendorf, formerly pro- 
fessor at the University of Wisconsin, and 
at present consulting engineer, with offices 
at 819 Chamber of Commerce Building, 
Chicago. Mr. Elmendorf has been promi- 
nent in the art of mechanical differentiation, 



102 Draft Gear Tests of the U. S. Railroad Administration 



two of his papers on the subject appearing 
in the Journal of the Franklin Institute for 
January and February, 1918. The differ- 
entiating machine is based on the principle 
of similar triangles, a large triangle al- 
ways being developed similar to a smaller 
differential triangle. The angle of the lat- 
ter being varied according to the tangent 
of the car-movement curve causes a similar 
change in the larger, or plotting triangle, 
and the instantaneous velocity is thus plot- 
ted continuously and directly from the 
original car-movement curves, and with a 
much greater degree of accuracy than is 
possible by laying off tangents. This same 
instrument was also used to produce the 
time-force curves directly from the velocity 
curves. The instrument is invaluable for 
determining mechanically the first deriva- 
tive of any curve. A photographic repro- 
duction of this instrument is shown in Fig. 
57. 

Energy Curves 

The energy curves shown in Fig. 80g 
have been produced by simple calculation 
from the preceding velocity curves. These 
energy values include not only the kinetic 
energy represented by the direct movement 
of the car as a whole, but also the energy 
of rotation of the wheels and axles, which 
in these cars amounts to an addition of 
2.83 per cent to the ordinarily considered 
energy of translation. The total kinetic 
energy in one of these cars (143,000 lb. 
gross weight) including the above rotative 
energy, may be conveniently determined 
by the formula 4918 V 2 , V being the car 
velocity in miles per hour. 

In this particular run (Westinghouse 
D-3 single gear at closing speed) the kin- 
etic energy of car A was reduced from 
35,308 ft. lb. to 8,427 ft. lb. by the com- 
pression of the gear, while at the same time 
the kinetic energy of car B was increased 
from zero to 8,427 ft. lb. The sum of the 



kinetic energies of the cars at this instant, 
(the instant of maximum draft gear com- 
pression) amounted to 16,854 ft. lb., so 
that the work done in compressing the draft 
gear and the car structure, and in over- 
coming rolling and grade resistance, 
amounted to 18,454 ft. lb. This quantity 
corresponds with the expression "work 
done" as applied to drop testing of draft 
gears. The dotted line beneath the line of 
zero energy represents the instantaneous 
value of work done at any instant during 
draft gear compression up to the instant 
of maximum draft gear closure. 

The energy curves during the period of 
draft gear release show the changes in 
kinetic energy produced in the cars by the 
recoil of the draft gear. In this particular 
run the recoil increased the kinetic energy 
of car A to 16,542 ft. lb. and reduced that 
of car B to 2,666 ft. lb., so that at the in- 
stant of parting the kinetic energy repre- 
sented by the movement of the two cars 
amounted to 19,208 ft. lb. The original 
kinetic energy of car A being 35,308 ft. 
lb., there was thus a total absorption in 
this run of 16,100 ft. lb., this quantity 
corresponding with the expression "work 
absorbed" as applied to drop testing of 
gears. 

The greatest possible absorption that 
could have taken place is always repre- 
sented by the maximum ordinate to the 
dotted curve beneath the line of zero en- 
ergy, and this point always coincides with 
the instant of maximum draft gear com- 
pression. During the period of compres- 
sion the sum of the kinetic energies of the 
two cars is decreasing, a portion of it being 
stored or absorbed by the draft gear. Dur- 
ing the period of release the draft gear re- 
turns more or less of this stored energy to 
the cars so that the sum of the kinetic en- 
ergies of the two cars is gradually increas- 
ing during the period of release. The giv- 
ing back of this energy is the measure of 



Draft Gear Tests of the U. S. Railroad Administration 



103 



absorption of the gear. In a gear of 100 result of this influence is separated from 



per cent absorption the dotted line would 
be horizontal throughout the release per- 
iod. In a perfect spring gear (no absorp- 
tion) the dotted line would be directed up- 
ward during this period, reaching the zero 
line at the instant of parting. 



true gear absorption. 

Time-Force Curves 

Fig. 80k shows the mean forces which 
develop between the two cars due to draft 
gear compression and release. The force is 



rs^. 




fllll^^ X V' * "\ i/ 








^y y 

^Kk 









Fig. 57 — Mechanical Differentiating Machine 



The maximum possible absorption of this 
run, therefore, was not the full energy of 
impact, 35,308 ft. lb., but 18,454 ft. lb., 
the work done in closing the gear; and as 
the absorption amounted to 16,100 ft. lb., 
the percentage of gear absorption in this 
run was 87.2 per cent. Some slight amount 
of this absortion was due to car resistance. 
In the tabulations (Figs. 62 and 64) the 



plotted against time, and the curve thus 
shows the building up of the force through- 
out the period of compression, to a peak at 
the point of maximum gear closure. Dur- 
ing the release period the force falls off 
suddenly in the case of a friction gear. 

The portion of the time-force curve to 
the left of the peak denotes mean draft gear 



104 Draft Gear Tests of the U. S. Railroad Administration 



compression forces while that to the right 
denotes the forces of release. 

In the absence of any more workable and 
reliable method, the force has been ob- 
tained by calculating the forces required 
to produce the recorded changes of ve- 
locity over a given period of time, using 
the commonly understood laws of motion. 
It is admitted that the force as determined 
is deduced from its effect and has not been 
directly measured. No means for directly 
measuring a dynamic force has ever been 
devised. Various methods of a more or less 
refined nature have been employed to de- 
ductively determine the force from one or 
another of its results. Among the simplest 
and most elementary of these methods is 
the deduction of the force from the ac- 
celeration of a moving body. The possi- 
bility of error must be recognized in this 
method of figuring. In fact, any effort to 
compute a force from the result of the 
force assumes a constancy and uniform 
continuance over some accepted period of 
time that is especially questionable in the 
case of draft gear resistance. Such an as- 
sumption does not recognize the probable 
presence of a succession of higher forces 
working through lesser periods of time 
which would be capable of producing and 
would produce the identical records as to 
acceleration as a considerably lower force 
working uninterruptedly over a longer per- 
iod of time. It is unquestionable that in 
many of the gears, probably in every case, 
the sticking and irregularity of gear clos- 
ure was accompanied by high forces which, 
because of their very limited duration, 
could not manifest themselves in the time- 
displacement curves. Such forces would 
produce a momentary penetration or over- 
compression of the car sills, and the very 
storing and release of this would in itself 
smooth out the car-movement curves. The 
mean or average forces and the ultimate 
peak forces as deduced in these curves, 



however, are substantially correct and it is 
questionable whether after all the mean 
force as depicted, or in other words the 
force supplied over a long enough period 
of time to produce penetration or to do the 
work of rupture, is not the real damaging 
factor. For the high force of but momen- 
tary duration could possibly do little more 
than to overcome the inertia of the contig- 
uous particles of the sills to which the 
force is first applied. 

The time-force curves will assist in an 
understanding of the fact that the force be- 
tween colliding cars is not governed or in 
any manner reduced by the action of a fric- 
tion gear over a spring gear of the same 
characteristics. Energy absorption has in 
itself no effect whatever upon the compres- 
sion line. But its influence is immediately 
apparent in the forces of release. For while 
it requires high forces to overcome the fric- 
tional resistance and to compress* a friction 
gear, the force immediately disappears 
when the gear starts to release. This ac- 
tion is clearly shown in the time-force 
curves. 

While the peaks of each of these time- 
force curves show the maximum pressure 
finally developed between the cars in the 
particular run, these peaks are not to be 
considered as the closing forces of the 
gear. This force is usually higher than the 
true ultimate resistance of the gear, due to 
the fact that it is not possible to control 
the car speeds delicately enough to just 
close the gears and not over-close them. A 
very slight over-solid speed will, in a 
sturdily constructed gear, produce an im- 
mediate increase in force, because of the 
very small yield of the gear housing. In 
the force-closure curves, which will be dis- 
cussed hereafter, the true force at the very 
point of gear closure is given and the re- 
sults of any slight over-closure are elimi- 
nated. It should not, however, be assumed 
from the foregoing that the closing speeds 



Draft Gear Tests of the U. S. Railroad Administration 



105 



as given for the various gears are only 
roughly approximate, as they were in all 
instances searched out by means of many 
runs at close intervals around the closing 
point. An over-solid velocity of even 0.05 
M.P.H. will, with a rigid gear construction, 
greatly increase the momentary peak of 
this force curve. 

Time-Closure Curves 

Time-closure curves are developed for 
each of the runs, Fig. 80n showing such a 
curve for the single gear run for the West- 
inghouse D-3 gear. Curve D in this figure 
has been derived and erected from the 
superimposed car-movement curves and 
shows the full yield that took place be- 
tween the cars, including draft gear com- 
pression, center sill compression, and side 
sill movement. This yield is plotted 
against time. Curve C is obtained by sub- 
tracting from Curve D the amount of the 
center sill yield and side sill movement, 
this having been determined from runs 
made at low speeds when both cars were 
equipped with solid steel blocks instead of 
draft gears. Curve C therefore represents 
the amount of and nature of the true draft 
gear action, all other influences being elimi- 
nated. Curve B was obtained from an en- 
tirely different source, namely, from the 
small drum carried by car B for recording 
the action of the draft gear in that car (see 
Figs. 49 and 50). Curves C and B show a 
remarkable coincidence for all of the gears, 
incidentally forming a valuable check upon 
the action of the entire set of recording in- 
struments. 

From the time-closure curve it will be 
seen that the draft gear in this run actually 
compressed 2.40 in., the difference between 
this figure and the nominal travel of 2 T 7 g 
in. being due to a shortness of £% in. in 
the length of the draft gear pocket in car 
B, the gear, in other words, being under 
g*5 in. more compression than normal. In 



general, throughout the tests, slight varia- 
tions will be found between the gear travels 
obtained in the car-impact tests and other 
tests. Such differences are due to the in- 
ability to adjust the gear to a nicety in the 
rough draft gear pockets of the cars. The 
actual point of gear closure was determined 
in each instance by the shearing of one or 
more lead records. The combined com- 
pression of the center sills and yield of the 
side sills of the two cars is represented by 
the maximum distance between the lines C 
and D, and in this particular instance 
amounted to 0.13 in. 

In the time-closure curve for the two 
Westinghouse gears, Fig. 80q, curves B, C 
and D are similar to curves B, C and D 
respectively of Fig. 80n. In this case, 
however, each car was equipped with a 
draft gear and the curve B, drawn by the 
draft gear of car B, shows the action of 
that gear only. Curve A has therefore been 
produced to show what the gear in car A 
was doing at the same time, these two 
curves when combined in the vertical scale 
producing curve C of the same figure. It will 
be seen that the two gears did not act in 
an entirely uniform manner, but that occa- 
sionally one of the gears would cease act- 
ing for an instant while the other moved. 
At other times both gears were acting. 
This character of action occurred both on 
compression and release, and was visible 
to the eye when closely watching the move- 
ment of the buffers. 

Force-Closure Curves 

In Fig. 80r is shown a force-closure 
curve for the closing run of Westinghouse 
D-3 gear (single gear run). This curve is 
produced directly from the time-force 
curve, Fig. 80r, and the time-closure curve, 
Fig. 80n, by the simple method of elimi- 
nating the time element from both of these 
curves and plotting the force directly 
against gear closure. This diagram cor- 



106 Draft Gear Tests of the U. S. Railroad Administration 



responds with the ordinary static card ex- 
cept that it represents the dynamic action 
of the gear. All of the force-closure dia- 
grams are drawn to the same scale as the 
static test diagrams, so that the dynamic 
and static force-closure cards may be di- 
rectly compared for the same gears. For 
example, this dynamic card, Fig. 80r, 
should be compared with the static card 
shown in Fig. 18 for the identical gear 
(test gear No. 2). 

These curves provide a valuable check 
upon the fact of complete gear closure. In 
this particular run a peak force of 207,000 
lb. was finally developed between the cars, 
but from the force-closure curve, Fig. 80r, 
it will be seen that the peak was reached 
when the gear was slightly over-solid and 
that the true solid point of the gear was at 
a load of 170,000 lb. This latter should 
therefore be taken as the ultimate dynamic 
resistance of this particular gear and is 
the true comparati/e measure of the load 
imposed upon the car sills at the instant of 
gear closure. In all cases a gear was not 
considered fully closed until one or more 
lead wires were sheared, following the usual 
practice as in drop testing; hence in almost 
every instance a very slight over-solid 
speed resulted from this effort to credit 
each gear with its full value. It requires 
but a very slight impact directly upon the 
gear barrel or housing to produce a high 
force peak, especially in a sturdily con- 
structed gear. 

The amount of work done and work 
absorbed may be figured from this card in 
the same manner as from the ordinary 
static card, these figures being given in 
later tabulations. In the double gear runs, 
Fig. 80t, the two gears did not do equal 
amounts of work, as can be seen from the 
superimposed work diagrams. 
Solid Buffer Runs 

The collision of two cars must always 
result in more or less penetration or yield 



of the car structures, the amount of the 
yield being dependent upon the sturdiness 
of the cars. In the car-impact tests the car- 
movement curves are obtained from the 
side sills of the cars. The records, there- 
fore, are for the movements of the side sills 
with respect to a fixed point along the 
track (the datum lines on the drums). The 
records accordingly do not represent the 
true and exact movements of the entire 
masses of the cars, but include the vibra- 
tions and relative movements of the side 
sills with respect to the center sills. In 
order to ascertain the yield of the Syming- 
ton test cars under different forces a series 
of runs was made with both cars equipped 
with solid steel blocks, 24 sq. in. cross sec- 
tional area, instead of draft gears. These 
were made at approximate impact speeds 
of %, %, %, 1, 1%, 2, 2% and 3 miles 
per hour. 

Special arrangements were made to ob- 
tain independent records of the yield of the 
center sills and the whip of the side sills. 
Certain fundamental data have been set up 
from these runs as to the yield of the cen- 
ter sills, the whip of the side sills, and the 
forces between cars with no draft gears, or 
the forces that should be expected from 
over-solid velocities with any gear, pro- 
vided it is as strong a column as the D 
coupler. These runs also give information 
in regard to work done and work absorbed 
by the car bodies and the lading. The 
records from the runs at approximate 
speeds of 1 M.P.H. and 2 M.P.H., together 
with the derived curves, are reproduced in 
Fig. 58. These curves, while appearing 
very small in comparison with the later 
curves made with draft gears in the cars, 
are reproduced to the same scale as the lat- 
ter and are directly comparable as to mag- 
nitude. 

The exact impact velocity in the first of 
these runs was 1.06 M.P.H., and 1.95 



Draft Gear Tests of the U. S. Railroad Administration 



107 



M.P.H. in the second. The period of con- 
tact was very short, the entire cycle being 
but 0.057 seconds in the first run and 0.063 
seconds in the latter run. In the first run 
the cars were in contact for 0.53 inches 
and for 1.09 inches in the second run. In 
the first run the maximum force was 
reached when car B had moved but ■£% in. 
and in the second run when it had moved 
but % in. 

In the matter of energy absorption, in 
run No. 1 there was a possible absorption 
of 2764 ft. lb. and an actual absorption of 
1775 ft. lb., or 64.2 per cent. In run No. 
2 the possible absorption was 9357 ft. lb. 
and the actual absorption 7607 ft. lb., or 
82.5 per cent. 

The curves, Figs. 59 and 60, have been 
plotted from the results of these runs. The 
first of these, Fig. 59, shows the combined 



yield of the two car bodies at various 
speeds of impact. The second, Fig. 60, 
shows the force developed between the cars 
at various speeds. These curves form the 
basis for the general deductions made for 
the influence of the car bodies throughout 
the tests. It should be remembered that 
these definite results are for the two par- 
ticular cars only, but it is believed that 
they are indicative of the performance of 
modern cars generally. Incidentally, this 
force-curve has been compared with a sim- 
ilar curve produced in an entirely different 
manner by Col. B. W. Dunn, Chief of the 
Bureau of Explosives, the two curves show- 
ing a remarkable coincidence. The yield 
of the car bodies and the whip of the side 
sills as determined in these runs form the 
basis for the corresponding corrections in 
the succeeding time-closure curves of the 
draft gears. 



108 



Draft Gear Tests of the U. S. Railroad Administration 



t: 2 



/mpoci~ Ve/ocrf~y=/o6M.P.H. 



/mpae-f- \/e/oc/-ty=/3s m.p.h. 




Sec ^//f^ OJ4 _Sec^e/eose 
■^ OS7 SecCyc^ 



,,- ^gc Cycle 

h— 063 *■ m 

7Tme- Seconds 
Fig. 58 — Curves from Solid Buffer Runs 



rorce- C/osure Diagrams. 



Impact Vthaty-/.OGMP.H. 



,J4 ^j/s,ooo m 



I 






Car Y/e/d—/nctiv9. 





Force- C/osure Diagrams. 


-JO- 


| 


1 

* eco 




Mpac-f Ve/ocfty, 

^/.SSMRH. 






















4Cd 


1 






1 






300 


1 






I 






2C0 


f 










/CO 


I 






\t_ 






y 





Car- Y/e/d — /ncAea. 



Draft Gear Tests of the U. S. Railroad Administration 109 



Y/ELD OF TEST CARS, 
WHEN COLUD/A/S,^/TROUT DRAFT SEARS. 



































0.1 






























































0.6 






























































as 

i? 


















































#&.- 


























xt> 


^ 


Jjs*^ 






















*\t 




x^ 
















^O.J 

3 










.\os 


V 


























A / 


yr 






















0.2 






























































OJ 































































































/ a 

/MPACT VELOC/TY- M.P.H. 

Fig. 59 — Plot of Car Body Yield at Varying Impact Velocities 



110 Draft Gear Tests of the U. S. Railroad Administration 



FORCE BETWEEN TEST CARS, 
WHENCOLL/D/MG, W/TH OUT DRAFT GEARS. 



































WOO 






























































/zoo 

i 






























^S { 




























Of 


































































soo 


















































O / 












<0 600 





















/ O 






























O 












6 

• 400 

0) 










































*$r 





















^s 200 


































































































/ 2. 

/MPACT VELOC/TY - M.RH. 

Fig. 60 — Plot of Force at Varying Impact Velocities 



DISCUSSION OF GEARS IN CAR-IMPACT TESTS 



As the first measure of a draft gear is its 
capacity, or reduced to terms of practice, 
the impact speed at which it will close, the 
performance of the several gears in the car- 
impact tests will be discussed in the order 
of the closing speeds of the test gears. The 
later tabulations also are arranged in this 
order. 

National H-l 

Gear No. 29 in Car B 
Gear No. 30, or Solid Buffer, in Car A 

These gears showed the highest capacity, 
both in the drop test and in the car-impact 
tests of any of the gears, and their action 
was good, considering the high closing 
speed. While the velocity curves show 
many slight irregularities, yet there were 
no violent disturbances. The closing run 
was at a velocity of 5.07 M.P.H., represent- 
ing almost eight times the energy of the 
closing run of the spring gear, and more 
than one and one-half times the energy of 
a run at 4 M.P.H., hence trembling of the 
car sides is to be expected. The gear ac- 
tion itself was not so smooth in the closing 
speed run, but the amount of gear action 
and the smoothness of car action at 1 
M.P.H. with two of these gears is surpris- 
ing. The two test gears went solid at an 
impact velocity of 5.07 M.P.H. and the 
single gear at 3.95 M.P.H. At 1.14 M.P.H, 
with two gears, the combined gear closure 
was 1.25 in. In the final run the average 
work done per gear was 27,184 ft. lb, and 
the average work absorbed 20,750 ft. lb, 
or a gear absorption of 76 per cent. The 
total energy loss in the run from all causes 
was 51,461 ft. lb, or 41 per cent of the 
original kinetic energy of the striking car. 
In this connection it should be noted that 
if the gears themselves were of 100 per 



cent absorption efficiency, the percentage of 
energy loss in the run from gear absorp- 
tion could not amount to more than 50 per 
cent of the original kinetic energy of car 
A. The gears were slightly over-solid, as 
can be seen from the force-closure curves, 
the force peak reaching 820,000 lb. in the 
run, whereas gear No. 29 closed at 390,000 
lb. and No. 30 at 550,000 lb. In all gears 
the closing point was determined by the 
shearing of lead wires and the regular 
practice was to just slightly exceed the 
capacity rather than to credit a gear with a 
reduced closing speed. But it should not 
be assumed that the run was far beyond the 
capacity of the gear, as in a sturdy gear 
such as the H-l a slight excess of energy 
delivered directly to the gear as a column 
will at once produce a high force peak. 
Based upon the average drop test value of 
this type of gear, a closing speed of 5.09 
M.P.H. with 143,000 lb. cars may be ex- 
pected from two average commercial gears 
of this type, with a closing force of 
466,000 lb. 

Sessions Type K 

Gear No. 11 in Car B 
Gear No. 12, or Solid Buffer, in Car A 

The action of these gears in the car-im- 
pact tests was not satisfactory. The gears 
closed in an irregular manner and the car 
movement curves are the roughest and most 
irregular obtained in the tests, indicating 
violent disturbance of the car and lading. 
The spring barrels of both gears scaled 
during the test and all of the springs had 
been solid. The two test gears closed at 
4.37 M.P.H. and the single gear at 3.81 
M.P.H. At 1.12 M.P.H, with two gears, 
the combined gear closure was 1.07 in, 
showing a satisfactory cushioning at this 



— Ill 



112 Draft Gear Tests of the U. S. Railroad Administration 



speed. In the final run the average work 
done per gear was 19,367 ft. lb., and the 
average work absorbed 16,375 ft. lb., or a 
gear absorption of 84% per cent. The 
total energy loss in the run from all causes 
was 43,040 ft. lb., or 45 per cent of the 
original kinetic energy of the striking car. 
The gears were slightly over-solid, the 
force peak in the run reaching 400,000 lb., 
while gear No. 11 closed at 260,000 lb. and 
gear No. 12 at 165,000 lb. Based upon the 
average drop test value of this type of gear, 
a closing speed of 4.33 M.P.H. with 143,- 
000 lb. cars, may be expected from two 
average commercial gears of this type, with 
a closing force of 210,000 lb. 

The velocity curves of this gear being 
especially irregular, it may be worth while 
to repeat here a previous notation regard- 
ing the mean velocity curves. After fol- 
lowing all the minute variations in the car 
movement curves with the mechanical dif- 
ferentiater and producing the irregular 
dotted curves, a second differentiation was 
made, following the trend of the car-move- 
ment curves rather than the local varia- 
tions. The mean velocity curves were estab- 
lished by this method. 

It is especially noticeable that the Ses- 
sions K gear, which in the drop test shows 
considerably less capacity than the Ses- 
sions Jumbo (18.8 in. Sessions K, 28.1 in. 
Sessions Jumbo), required an impact 
velocity of 4.40 M.P.H. to close two gears, 
whereas two Jumbo gears, to be discussed 
later, required a speed of but 4.22 M.P.H. 

Miner A-18-S 

Gear No. 23 in Car B 
Gear No. 24, or Solid Buffer, in Car A 

These gears showed high capacity in the 
car-impact tests. The car-movement curves 
show some irregularities and the derived 
velocity curves, while not smooth, are good 
for a run of this high speed. The gear ac- 
tion was good except when nearly closed, 



where some pulsations occurred. The two 
gears did not work uniformly, one being 
almost closed before the other had com- 
pressed more than y 8 in. This does not 
mean that at any time there was a lack of 
cushioning between the cars, as either one 
or the other of the two gears was yielding 
at all points of the gear cycle. Such alter- 
nating action between the two gears is 
typical of friction draft gears. Likewise 
on the release, the gears operated alter- 
nately but positively. The two test gears 
went solid at an impact velocity of 4.46 
M.P.H. and the single gear at 3.57 M.P.H. 
At 1.06 M.P.H. with two gears the com- 
bined gear closure was 0.64 in. In the 
final run the average work done per gear 
was 18,717 ft. lb. and the average work 
absorbed 13,334 ft. lb., or a gear absorp- 
tion of 71 per cent. The total loss in the 
run from all causes was 40,990 ft. lb., or 
42 per cent of the original kinetic energy 
of the striking car. The gears were slightly 
over-solid, as can be seen from the force- 
closure curves, the force peak reaching 
640,000 lb. in the run, whereas gear No. 
23 closed at 390,000 lb. and gear No. 24 at 
390,000 lb. Based upon the average drop 
test value of this type of gear, a closing 
speed of 4.33 M.P.H. with 143,000 lb. cars 
may be expected from two average com- 
mercial gears of this type, with a closing 
force of 368,000 lb. 

Westinghouse NA-1 

Gear No. 7 in Car B 
Gear No. 8, or Solid Buffer, in Car A 

The Westinghouse type NA-1 gears in 
the car-impact tests' were highly satisfac- 
tory. Both the gear action and the car 
action were especially smooth, although 
the two gears did not act together either on 
compression or release. The velocity curves 
show the least disturbance of cars and lad- 
ing found in any gear, except in the case 



Draft Gear Tests of the U. S. Railroad Administration 



113 



of a few of the very low capacity ones. The 
two test gears went solid at an impact 
velocity of 4.16 M.P.H. and the single gear 
at 3.06 M.P.H. At 0.96 M.P.H, with two 
gears, the combined gear closure was 1.62 
in. In the final run the average work done 
per gear was 19,167 ft. lb. and the average 
work absorbed 16,717 ft. lb., or a gear 
absorption of 87 per cent. The total 
energy loss in the run from all causes was 
39,370 ft. lb., or 46 per cent of the orig- 
inal kinetic energy of the striking car. The 
gears were slightly over-solid, as can be 
seen from the force-closure curves, the 
force peak reaching 500,000 lb. in the run, 
whereas gear No. 7 closed at 158,000 lb. 
and No. 8 at 187,000 lb. The curves made 
with this gear, which has 3 in. travel, show 
clearly the value of increased length of 
draft gear travel. Based upon the average 
drop test value of this type of gear, a clos- 
ing speed of 4.24 M.P.H. with 143,000 lb. 
cars may be expected from two average 
commercial gears of this type, with a clos- 
ing force of 179,000 lb. 

National M-l 

Gear No. 32 in Car B 

Gear No. 33, or Solid Buffer, in Car A 

These gears in the car-impact tests 
showed rather irregular gear action. The 
car-movement curves, however, are not bad 
considering the speed of the run, and the 
velocity curves do not indicate a violent 
disturbance of the cars. The two test gears 
went solid at an impact velocity of 4.26 
M.P.H. and the single gear at 3.08 M.P.H. 
At 1.06 M.P.H., with two gears, the com- 
bined gear closure was 1.10 in. In the 
final run the average work done per gear 
was 20,000 ft. lb., and the average work 
absorbed 16,784 ft. lb., or a gear absorp- 
tion of 84 per cent. The total energy loss 
in the run from all causes was 40,312 ft. 



lb., or 45 per cent of the original kinetic 
energy of the striking car. The gears were 
slightly over-solid, as can be seen from the 
force-closure curves, the force peak reach- 
ing 580,000 lb. in the run, whereas gear 
No. 32 closed at 400,000 lb. and No. 33 at 
218,000 lb. Based upon the average drop 
test value of this type of gear, a closing 
speed of 4.22 M.P.H. with 143,000 lb. cars 
may be expected from two average com- 
mercial gears, with a closing force of 303,- 
000 lb. 



Sessions Jumbo 

Gear No. 14 in Car B 

Gear No. 15, or Solid Buffer, in Car A 

This gear made a much better showing 
in the car-impact tests than the previous 
Sessions K gear. In fact, for a gear of its 
capacity, its action is not unsatisfactory. 
This gear again demonstrates the value of 
longer gear travel. The two test gears 
closed at 4.30 M.P.H. and the single gear 
at 3.26 M.P.H. At 1.02 M.P.H., with two 
gears, the combined gear cjosure was 1.14 
in. In the final run, with two gears, the 
average work done per gear was 19,025 ft. 
lb., and the average work absorbed 14,317 
ft. lb., or a gear absorption of 75 per cent. 
The total energy loss in the run from all 
causes was 35,660 ft. lb., or 39 per cent of 
the original kinetic energy of the striking 
car. The gears were slightly over-solid, 
the force peak in the run reaching 465,000 
lb., while gear No. 14 closed at 137,000 lb. 
and gear No. 15 at 250,000 lb. Based upon 
the average drop test value of this type of 
gear, a closing speed of 4.22 M.P.H. with 
143,000 lb. cars may be expected from two 
average commercial gears, with a closing 
force of 186,000 lb. The relationship be- 
tween the drop tests and the car-impact 
tests of this gear is much closer than in the 
Sessions Type K. 



114 



Draft Gear Tests of the U. S. Railroad Administration 



National M-4 

Gear No. 35 in Car B 
Gear No. 36, or Solid Buffer, in Car A 

The M-4 gear is the smoothest acting and 
most regular of the National gears, and 
also shows the highest percentage of ab- 
sorption. It also shows the lowest ultimate 
resistance. The individual gears did not 
work together, but the car-movement curves 
and the velocity curves, considering the 
impact velocity, are satisfactory. The two 
test gears went solid at an impact velocity 
of 4.12 M.P.H., and the single gear at 3.88 
M.P.H. At 1.06 M.P.H., with two gears, 
the combined gear closure was 1.10 in. In 
the final run the average work done per 
gear was 18,467 ft. lb., and the average 
work absorbed 15,817 ft. lb., or a gear 
absorption of 86 per cent. The total energy 
loss in the run from all causes was 38,670 
ft. lb., or 46 per cent of the original kinetic 
energy of the striking car. The gears were 
slightly over-solid, as can be seen from the 
force-closure curves, the force peak reach- 
ing 360,000 lb. in the run, whereas gear 
No. 35 closed at 159,000 lb. and No. 36 at 
138,000 lb. Based upon the average drop 
test value of this type of gear, a closing 
speed of 4.03 M.P.H. with 143,000 lb. cars 
may be expected from two average com- 
mercial gears, with a closing force of 143,- 
000 lb. 

Cardwell G-18-A 

Gear No. 20 in Car B 
Gear No. 21, or Solid Buffer, in Car A 

The action of these gears in the car-im- 
pact tests was satisfactory. The gear is of 
3 i 3 (r in. travel and this is apparent in length 
of gear cycle and track movement of cars 
during the gear cycle. The G-18-A gears 
have less initial compression thantheG-25-A 
gears, and this is reflected in the greater 
yield of the two gears in the runs at ap- 



proximately 1 M.P.H. The two test gears 
went solid at an impact velocity of 3.85 
M.P.H. and the single gear at 2.79 M.P.H. 
At 1.10 M.P.H., with two gears, the com- 
bined gear closure was 1.32 in. In the 
final run the average work done per gear 
was 17,117 ft. lb., and the average work 
absorbed 15,575 ft. lb., or a gear absorp- 
tion of 91 per cent. The total energy loss 
in the run from all causes was 35,476 ft. 
lb., or 49 per cent of the original kinetic 
energy of the striking car. The gears were 
slightly over-solid, as can be seen from the 
force-closure curves, the force peak reach- 
ing 295,000 lb. in the run, whereas gear 
No. 20 closed at 110,000 lb. and No. 21 at 
186,000 lb. Based upon the average drop 
test value of this type of gear a closing 
speed of 3.89 M.P.H. with 143,000 lb. cars 
may be expected from two average com- 
mercial gears, with a closing force of 214,- 
000 lb. 

Cardwell G-25-A 

Gear No. 17 in Car B 

Gear No. 18, or Solid Buffer, in Car A 

The test gears of this type were, as here- 
tofore explained, of higher capacity than 
commercial gears of the same type pre- 
viously tested. Consequently it required a 
higher impact velocity (4.05 M.P.H.) to 
close the two test gears than is to be ex- 
pected from the average product. But even 
though of abnormal capacity the Cardwell 
test gears showed smooth action both as to 
gears and cars. In fact, for its capacity, it 
stands in this respect as one of the most 
satisfactory of the gears. It is not to be 
expected that any gear of higher capacity 
will give the ease of car movement and the 
smoothness of gear action shown by spring 
gear with and at its lower capacity. But 
when a friction gear with a closing capacity 
of 4 M.P.H. and of 2% in. travel or less 
shows reasonably smooth velocity curves in 



Draft Gear Tests of the U. S. Railroad Administration 



115 



these tests, it may be accepted as a satis- 
factory gear so far as the service perform- 
ances of the new gear is concerned. The 
single test gear went solid at 2.97 M.P.H. 
At 0.92 M.P.H. the combined travel of the 
two gears was 0.60 in., reflecting the high 
initial compression of these gears. In the 
final run the average work done per gear 
was 17,917 ft. lb., and the average work 
absorbed 15,534 ft. lb., or a gear absorp- 
tion of 87 per cent. The total energy loss 
in this run from all causes was 38,190 ft. 
lb., or 47 per cent of the original kinetic 
energy of the striking car. These gears in 
the run at 4.05 M.P.H. were slightly over- 
solid. The force peak reached in the run 
was 368,000 lb., whereas gear No. 17 went 
solid at 295,000 lb. and gear No. 18 at 
315,000 lb. Based upon the average drop 
test value of this type of gear, a closing 
speed of 3.86 M.P.H. (143,000 lb. cars) 
may be expected from two average com- 
mercial gears, with a closing force of 277,- 
000 lb. 

Westinghouse D-3 

Gear No. 2 in Car B 
Gear No. 3, or Solid Buffer, in Car A 

In all the runs the Westinghouse D-3 
gear showed smooth and regular gear ac- 
tion and a noticeable absence of shock to 
cars and lading. The two gears closed at 
3.65 M.P.H., and the single gear at 2.68 
M.P.H. At 1.13 M.P.H., with two gears, 
the combined gear closure was 2.44 in., re- 
flecting the easy initial movement of this 
gear. The draft gear action, while slightly 
variable between the two gears in the 
double gear runs, is exceptionally good. 
The velocity curves are good for a friction 
gear of this capacity. In the final run the 
average work done per gear was 14,667 ft. 
lb., and the average work absorbed 12,167 
ft. lb., or a gear absorption of 83 per cent. 
The total energy loss in this run from all 
causes was 29,864 ft. lb., or 46 per cent of 



the original kinetic energy of the striking 
car. The final run was just slightly over- 
solid, as can be seen from the force-closure 
diagram. The peak of the force curve 
reached 285,000 lb., gear No. 2 closing at 
195,000 lb. and gear No. 3 at 240,000 lb. 
Based Upon the average drop test value of 
this type of gear a closing speed of 3.59 
M.P.H. (143,000 lb. cars) may be expected 
from two average commercial gears, with a 
closing force of 210,000 lb. 

Gould 175 

Gear No. 41 in Car B 
Gear No. 42, or Solid Buffer, in Car A 

The Gould gears showed smooth action, 
but high recoil. The two test gears closed 
at 3.56 M.P.H. and the single gear at 2.72 
M.P.H. At 0.96 M.P.H., with two gears, 
the combined gear closure was 1.63 in. 
The velocity curves, while not bad, are yet 
more irregular than other gears of equal 
capacity. In the final run the average work 
done per gear was 13,767 ft. lb., and the 
average work absorbed 10,100 ft. lb., or a 
gear absorption of 73 per' cent. The total 
energy loss in this run from all causes was 
24,523 ft. lb., or 39 per cent of the original 
kinetic energy of the striking car. These 
gears also were slightly over-solid, the 
force peak in the run reaching 405,000 lb. ; 
gear No. 41 closed at 260,000 lb. and gear 
No. 42 at 230,000 lb. Based upon the aver- 
age drop test value of this type of gear, a 
closing speed of 3.59 M.P.H. with 143,000 
lb. cars may be expected from two average 
commercial gears, with a closing force of 
249,000 lb. 

Murray H-25 

Gear No. 38 in Car B 
Gear No. 39, or Solid Buffer, in Car A 

In the car-impact tests, as in all the tests 
of the full program, the Murray gear 



116 Draft Gear Tests of the U. S. Railroad Administration 



showed exceptionally smooth and regular 
action. The car movement curves and 
velocity curves are among the best, consid- 
ering the speed of impact, and indicate that 
there was no violent disturbance of the cars 
and lading. The two test gears closed at a 
speed of 3.45 M.P.H. with the 143,000 lb. 
cars, and the single gear at 2.76 M.P.H. At 
0.98 M.P.H. the combined travel of two 
gears was 0.92 in., reflecting the higher 
initial resistance of this gear. In the final 
run the average work done per gear was 
13,900 ft. lb., and the average work ab- 
sorbed 11,584 ft. lb., or a gear absorption 
of 83 per cent. The total energy loss in 
this run from all causes was 27,730 ft. lb., 
or 47 per cent of the original kinetic energy 
of the striking car. The gears were slightly 
over-closed, the force of impact finally 
reaching a peak of 315,000 lb., gear No. 38 
closing at 210,000 lb. and gear No. 39 at 
130,000 lb. Based upon the average drop 
test value of this type of gear, a closing 
speed of 3.52 M.P.H. (143,000 lb. cars) 
may be expected from two average com- 
mercial gears, with a closing force of 
227,000 lb. 

Christy 

Gear No. 52 in Car B 
Gear No. 53, or Solid Buffer, in Car A 

This gear, closing at a comparatively 
low speed, produced irregular and erratic 
gear closure curves and unsatisfactory car- 
movement curves'. Even the low speed runs 
were not smooth and regular as in most 
gears. The velocity curves indicate a vio- 
lent disturbance of the cars. The two test 
gears went solid at an impact velocity of 
3.73 M.P.H. and the single gear at 3.56 
M.P.H. At 1.06 M.P.H., with two gears, 
the combined gear closure was 0.84 in. In 
the final run the average work done per 
gear was 12,934 ft. lb., and the average 
work absorbed 10,909 ft. lb., or a gear 



absorption of 84 per cent. The total energy 
loss in the run from all causes was 32,026 
ft. lb., or 47 per cent of the original kinetic 
energy of the striking car. The gears were 
slightly over-solid, as can be seen from the 
force-closure curves, the force peak reach- 
ing 370,000 lb. in the run, whereas gear 
No. 52 closed at 194,000 lb. and No. 53 at 
150,000 lb. Based upon the average drop 
test value of this type, of gear, a closing 
speed of 3.50 M.P.H. with 143,000 lb. cars 
may be expected from two average com- 
mercial gears, with a closing force of 
151,000 lb. 

Miner A-2-S 

Gear No. 26 in Car B 
Gear No. 27, or Solid Buffer, in Car A 

The Miner A-2-S gear showed good ac- 
tion but rather low capacity in the car- 
impact tests. Both the car action and gear 
action were especially smooth and among 
the most satisfactory in the tests. It is 
noticeable that in the final run with two 
gears, the gear in car A closed entirely be- 
fore the gear in car B began, to compress. 
The two test gears went solid at an impact 
velocity of 3.21 M.P.H. and the single gear 
at 2.47 M.P.H. At 1.07 M.P.H., with two 
gears, the combined gear closure was 0.81 
in., reflecting the high initial resistance of 
these gears. In the final run the average 
work done per gear was 10,025 ft. lb. and 
the average work absorbed 8,417 ft. lb., or 
a gear absorption of 84 per cent. The total 
energy loss in the run from all causes was 
24,754 ft. lb., or 49 per cent of the original 
kinetic energy of the striking car. The 
gears were slightly over-solid, as can be 
seen from the force-closure curves, the 
force peak reaching 525,000 lb. in the run, 
whereas gear No. 26 closed at 105,000 lb. 
and No. 27 at 68,000 lb. This high force 
peak, at a very slight excess of energy, re- 
flects the sturdy nature of the barrel of this 
gear when called upon to function as a 



Draft Gear Tests of the U. S. Railroad Administration 



117 



column in over-solid blows. Based upon 
the average drop test value of this type of 
gear, a closing speed of 3.26 M.P.H. with 
143,000 lb. cars may be expected from two 
average commercial gears, with a closing 
force of 89,000 lb. 

Waugh Plate Type 

Gear No. 49 in Car B 
Gear No. 50, or Solid Buffer, in Car A 

The Waugh gear showed excellent re- 
sults in the car-impact tests, although its 
capacity is limited. The ease with which 
the standing car is set in motion, considered 
alone, must commend this gear. Even 
though showing a high ultimate force, the 
regularity with which the force is built up 
eases off the blow and prevents severe 
shocks and vibrations. The curves show, 
however, that the action is almost entirely 
spring action, the absorption being low. 
The two test gears went solid at an impact 
velocity of 3.02 M.P.H. and the final run of 
the single gear was at 1.94 M.P.H. The 
records from this run show, however, that 
the single gear was not solid at this speed 
and that the gear should have been given 
an impact at 2.20 M.P.H. to fully close the 
one gear. At 1.06 M.P.H., with two gears, 
the combined gear closure was 2.34 in., 
showing a very high yield at this low speed. 
In the final run the average work done per 
gear was 9,100 ft. lb., and the average work 
absorbed 4,117 ft. lb., or a gear absorption 
of 45 per cent. The total energy loss in the 
run from all causes was 10,818 ft. lb., or 24 
per cent of the original kinetic energy of 
the striking car. The gears were just closed, 
as can be seen from the vertical direction 
of the force-closure curves. The force peak 
reached 335,000 lb. in the run, and gear 
No. 49 closed at this point. Gear No. 50 
closed at 285,000 lb. Based upon the aver- 
age drop test value of this type of gear, a 
closing speed of 2.98 M.P.H. with 143,000 



lb. cars may be expected from two average 
commercial gears, with a closing force of 
302,000 lb. 

Bradford K 

Gear No. 46 in Car B 
Gear No. 47, or Solid Buffer, in Car A 

This gear in the car-impact tests showed 
the same unsatisfactory conditions as to the 
development of the design as in the pre- 
vious laboratory tests. The springs went 
solid before the housing came together, 
thus setting up abnormal wedging forces 
and high ultimate resistance. One of the 
rockers cracked during these tests. The 
gears were of low capacity, the curves 
showing almost entirely spring action with 
but little friction. This can be readily seen 
by comparing the compression and release 
periods of the gear cycle, which are almost 
equal. The two test gears went solid at an 
impact velocity of 2.78 M.P.H. and the 
single gear at 2.04 M.P.H. At 1.12 M.P.H., 
with two gears, the combined gear closure 
was 2.67 in., this being the maximum yield 
obtained from any of the gears in the low 
speed run. In the final run the average 
work done per gear was 6,833 ft. lb., and 
the average work absorbed 2,150 ft. lb., or 
a gear absorption of 31 per cent. The total 
energy loss in the run from all causes was 
9,835 ft. lb., or 26 per cent of the original 
kinetic energy of the striking car. While 
the heads never came together, the gears 
were slightly over-solid on the springs, the 
force peak reaching 340,000 lb. in the run, 
whereas gear No. 46 closed at 270,000 lb. 
and No. 47 at 220,000 lb. In view of the 
defective design of this gear it is hardly 
proper to set values to be expected from 
the commercial gears from these test re- 
sults. But following the same methods 
used for grading all other gears, namely, 
based upon the average drop test value 
found for this type of gear, a closing speed 



118 Draft Gear Tests of the U. S. Railroad Administration 



of 2.87 M.P.H. with 143,000 lb. cars may 
be expected from two average commercial 
gears, with a closing force of 252,000 lb. 

Harvey Springs 

Gear No. 55 in Gar B 
Gear No. 56, or Solid Buffer, in Car A 

Two 8 in. x 8 in. Harvey springs, 
throughout the tests, constituted one gear 
unit, and in the car-impact tests these 
springs were applied in twin fashion, one 
above the other, with a horizontal yoke. 
The gear action was reasonably smooth, 
but it is noticeable that most of the yield 
of the springs had taken place at 1 M.P.H. 
The car-impact tests of these springs show 
the same character of compression line as 
found in the static test and the gear absorp- 
tion shows furthermore that the high force 
is the result of friction. The two gears 
went solid, or reached the previously de- 
termined statically solid point of travel, at 
an impact velocity of 2.33 M.P.H. and the 
single gear at 1.97 M.P.H. At 1.02 
M.P.H., with two gears, the combined gear 
closure was 2.62 in. In the final run the 
average work done per gear was 4,992 ft. 
lb., and the average work absorbed 2,709 
ft. lb., or a gear absorption of 54 per cent. 
The total energy loss in the run from all 
causes was 8,074 ft. lb., or 30 per cent of 
the original kinetic energy of the striking 
car. The gears at this run had reached a 
solid condition, as can be seen from the 
vertical trend of the force-closure curves, 
and also from the increasing roughness of 
the car-movement curves and the irregu- 
larities at the top of the time-closure 
curves. The force peak reached 490,000 
lb. in the run, whereas gear No. 55 closed 
at 245,000 lb. and No. 56 at 300,000 lb. 
Based upon the average drop test value of 
this type of gear, a closing speed of 2.27 
M.P.H. with 143,000 lb. cars may be ex- 



pected from two commercial gears, with a 
closing force of 259,000 lb. 

Class G Coil Springs 

Gear No. 58 in Car B 
Gear No. 59, or Solid Buffer, in Car A 

Two Class G springs, throughout the 
tests, constituted one gear unit, and in the 
car-impact tests the springs were applied in 
twin fashion, one above the other, with a 
horizontal yoke. The coils were not pro- 
tected from going solid. The curves ob- 
tained from these springs represent the best 
action obtained, both as to gear action 
and smooth and gradual movement of the 
cars. From the velocity curves it will be 
seen that the cars were eased off with no 
vibrations or disturbance whatsoever. The 
capacity, however, is extremely limited and 
the spring recoil almost 100 per cent. It is 
of especial interest to note that car A came 
to rest by the time the cars parted, and that 
car B, at parting, had almost the initial 
velocity of car A, this indicating practi- 
cally total recoil of energy. Another point 
of interest, and also reflecting the absence 
of gear absorption, is that the time of draft 
gear release is practically the same as that 
of draft gear compression. In fact, if the 
car-movement curve of car A is reversed 
and laid upon that of car B the two curves 
will be found to almost coincide. 

The two test gears went solid at an im- 
pact velocity of 1.84 M.P.H. and the single 
gear at 1.45 M.P.H. At 1.07 M.P.H., with 
two gears, the combined gear closure was 
2.00 in. In the final run the average work 
done per gear was 4,117 ft. lb., and the 
average work absorbed 450 ft. lb., or a 
gear absorption of 11 per cent. The total 
energy loss in the run from all causes was 
2,205 ft. lb., or 13 per cent of the original 
kinetic energy of the striking car. The 
gears were just solid, as can be seen from 
the force-closure curves, the force peak 



Draft Gear Tests of the U. S. Railroad Administration 119 



reaching 78,000 lb. in the run, whereas 
both gears closed at 60,000 lb. Based upon 
the average drop test value of this type of 
gear, a closing speed of 1.87 M.P.H. with 
143,000 lb. cars may be expected from the 
use of two Class G springs per car, with a 
closing force of 62,000 lb. 

The spring gears were the final ones in 
the car-impact tests, the Westinghouse D-3 
being the first. The excellence of both sets 
of runs is a check upon the uniform condi- 
tion of the cars and the instruments 
throughout the full series of tests. 

Summary of Car-Impact Tests 

It will be understood that the car-impact 
tests were made upon two gears only of 
each type. The table, Fig. 61, shows in 
Columns 3 and 4 the drop test values of 
the two test gears used for this purpose and 
of two average commercial gears respec- 
tively. In Columns 5 and 6 are then given 
the closing speeds of the two test gears and 
the closing speed that may be expected 
from two commercial gears. This latter 
quantity is based upon the relative drop 
test values of the test gears and the com- 
mercial gears. The three general tabula- 
tions, Figs. 62, 63 and 64, have been pre- 
pared to summarize the actual performance 
of the test gears in the car-impact tests. In 
these tabulations the gears appear in the 
order of the closing speeds of the com- 
mercial gears and have been classified ac- 
cording to closing speeds. In studying the 
performance of the car and the action of 
the gears there is but little interest in com- 
paring a low speed gear with a high speed 
gear. The interest lies in comparing the 
action of and the results from the use of 
gears of different types and of approxi- 
mately equal capacities. The gears have 
accordingly been grouped in these and suc- 
ceeding tables into four classes, as follows: 



Class 1: Gears closing at 5 M.P.H. and over. 

National Type H-l. 
Class 2: Gears closing at from 4 to 5 M.P.H. 

Sessions Type K. 

Miner Type A-18-S. 

Westinghouse Type NA-1. 

National Type M-l. 

Sessions Jumbo. 

National Type M-4. 

Class 3: Gears closing at from 3 to 4 M.P.H. 
Cardwell Type G-18-A. 
Cardwell Type G-25-A. 
Westinghouse Type D-3. 
Gould Type 175. 
Christy. 
Miner Type A-2-S. 

Class 4: Gears closing at less than 3 M.P.H. 
Waugh Plate. 
Bradford Type K. 
Harvey, two 8 in. x 8 in. springs, 
Coil Springs, two 8 in x 8 in., 
Class G. 

In the above classification of gears it 
will be noticed that while the Cardwell 
G-25-A test gears actually closed at 4.05 
M.P.H., yet from the table, Fig. 61, it will 
be seen that the average commercial gears 
of this type properly fall in Class 3, and 
this gear has accordingly been entered in 
this class in the general tabulations. Like- 
wise the test gears of the Waugh type ac- 
tually required 3.02 M.P.H. to close them, 
but from the average commercial gear this 
type belongs in Class 4. Asterisks (*) 
have been placed opposite these gears in 
the tables because of this fact. 

The table, Fig. 62, gives the results of 
the car-impact tests at the closing speed 
runs, using a test gear in each car; that of 
Fig. 63 the results at impact velocities of 
approximately 1 M.P.H. with a test gear in 
each car; and that of Fig. 64 the results at 
the closing speed runs with a test gear in 
car B only, car A being equipped with a 
solid steel block instead of a draft gear. 
These tables need no especial explanation 



120 Draft Gear Tests of the U. S. Railroad Administration 



except that it will again be stated that the 
results as tabulated are for test gears. The 
comparative action of average commercial 
gears, from which gear ratings should be 
deduced, are shown in a later table, Fig. 67. 

One of the most noticeable facts brought 
out by the general action of the gears in 
the car-impact tests is that draft gears are 
closed and the maximum force is delivered 
to the cars before the standing car (car B) 
has moved any material distance along the 
track. The maximum distance car B had 
moved in any of the tests at the instant of 
maximum force was with the Sessions 
Jumbo gear, and amounted to 1.59 in. 
From this it decreased to 0.43 in. with the 
Harvey springs. This shows that the force 
between colliding cars is substantially the 
same, whether the struck car be standing 
alone or at the head of a draft of cars, as 
in classification yards. Furthermore, it 
shows that the force of impact does not 
extend throughout the sills from end to 
end, in a horizontal line, but that it is di- 
vided into many components, the average 
of which must be directed toward the cen- 
ter of gravity of the entire mass, and that 
it gradually decreases in magnitude, due to 
the fact that each increment of the load re- 
sists the force in proportion to its own 
inertia. As a further demonstration of 
this, a run was made with a test gear in car 
B only. At an impact speed of 1.98 M.P.H. 
the gear closed l 1 /^ in. All of the wheels 
of the standing car (car B) were then 
blocked, and the run repeated, car A being 
released from the same station. In this 
run the impact speed was 2.02 M.P.H. and 
the draft gear closed 1^- in., or just g 1 ^ in. 
more than in the preceding run when car 
B was free to move off. In the second run 
the wheels of car B slid 1% in. along the 
track. 

A point of some interest is with respect 
to the position of the gears in the cars; 



whether the gear in the striking car or the 
standing car tends to close first. A number 
of double gear runs were made, changing 
the gears from one car to the other. A 
number of single gear runs were also made, 
using a test gear in car B, with the solid 
buffer in car A, and then placing the same 
gear in car A and applying the solid buffer 
to car B. No difference in gear action 
occurred from these manipulations, and 
the tests showed conclusively that the loca- 
tion of the gear, whether in car A or car B, 
is immaterial. 

When but one of the two cars is equip- 
ped with a gear the action is restricted to 
that gear, and laboratory tests are more 
nearly reproduced. Throughout the tests 
the gears used in car B for the single gear 
runs had been previously tested in the 
laboratory, and a direct comparison of in- 
dividual gear action in service and labora- 
tory operation can thus be made by means 
of the single gear runs. The time-closure 
curves show generally that when but one 
car is equipped with a gear the line of 
actual gear action corresponds closely with 
the derived line of gear action (lines B and 
C, time-closure curves). In the double 
gear runs, however, where two gears are 
working in opposition, and one or both of 
them may operate or stick, it will be seen 
that almost invariably the closure takes 
place by a succession of alternating move- 
ments between the two gears. 

Another point of interest in comparing 
these two classes of runs is in connection 
with the gear capacities, or, in other words, 
the closing speed when using one gear of 
the type or using two gears of the type. 
The table, Fig. 65, has been prepared to 
show the relative performance of the single 
gears and double gears of each type. In 
this table Column 3 gives the actual closing 
speed when using the two test gears. Col- 
umn 4 shows the calculated impact speed 



Draft Gear Tests of the U. S. Railroad Administration 



121 



MAKE AND 

TYPE or 

GEAR 


% 


COMBMD 
DROP 

TESF 
WU/EOF 

T7/ES£TW0 
TESFGFAK 


COMBINEO 
DROP TEST 
VALUE OF 

TWO 
AVERAGE 
COAfAfER- 
CIALGEARS 


ACTUAL 
CLOSING 

SPEED 
W/TH TWO 
TEST GEARS 

M.R. H. 


CLOSIA/6 
SPEED WITH 
TWO AVERAGE 
COMMERCIAL 

SEARS 
A4. R. H. 


W 


(3 


© 


(£ 


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@ 


WE5T/A/GH U5E 
D-3 


O CAR 


4AO " 


39.6" 


3.65 


3.59 


s CAR 


WEST/N6H0U5E 
NA~/ 


7 C/ B R 


5/.0 " 


52.0 ' 


4.16 


4.24 


QCAR 


SESS/ON5 
A 


//**" 


38./ " 


37.6 " 


4.37 


4.33 


/£<%" 


SESSIONS 
i/UMSO 


f4°a R 


56./ " 


56.2 " 


4.30 


4.22 


IS™ 


CAPDWELL 
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/7«iT 


4/. 5 ' 


37.8 " 


4.05 


3.66 


/A CAR 
/O x\ 


CARDWELL 
G-/8-A 


20%* 


36.5 " 


39.2 " 


3.85 


3.89 


2I CA » 


M/NER 
A-/Q-S 


23 c %" 


42./ " 


39.6 " 


4.46 


4.33 


24 C T 


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A-2S 


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26.0 " 


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3.2/ 


3.26 


21 C * R 


NAT/ ON A L 


29%" 


62.0 " 


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5.07 


5.09 


30 c £" 


NATIONAL 
M-/ 


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39. / " 


38.4 " 


4.26 


4.22 


33 C T 


NATIONAL 
M~4 


35*%* 


45.0 


43.0 " 


4J2 


4.03 


36 c «" 


MURRAY 
H-25 


38 c %" 


33.3 


34.0 " 


3.45 


3.52 


39 c ** 


GOULD 
/7S 


jjCAR 


35.9 " 


36.2 " 


3.56 


3.59 


42 C * R 


BRADFORD 
A- 


45 CAR 


20.9 ' 


2/.6 ' 


2.78 


2.67 


47°*? 


WAUGH 
PLATE 


49 car 


28.5 ' 


27.8 " 


3.02 


2.98 


so c Z" 


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^ryt «• 


39.2 " 


3.73 


3.50 


53 c £" 


fr*f-.0 


HARVEY 
2'Q"x8"8PGS. 


55 C £ R 


20.6 " 


/9.0 


2.33 


2.27 


S6 c r 


CO/L SPR/NGS 
Z-&erCLASS G 


5Q CA g 


//.4 


//.6 ' 


/.S4 


/.S7 


59 c «r 


Note*- The above speeds are* for two 
cor5 y each of /43 t OOO Lbs. total ' we/'gfit 



Fig. 61 — Tabulation of Closing Speeds 
of Gears: Car-Impact Tests 



122 Draft Gear Tests of the U. S. Railroad Administration 



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128 Draft Gear Tests of the U. S. Railroad Administration 



at which the single gear in car B should 
have closed, provided it functioned exactly 
as in the double gear run, the test gear 
having been removed from car A. This 
expected closing speed is based upon the 



relative work done by the two gears in the 
double gear runs, the work done by the 
two car structures being constant. Column 
5 gives for comparison the actual speed re- 
quired to close the single test gear in car B. 



PIT 



Hi 



life 







B8j 






^re^cs 



West/nghouseL 

P-3 



CAR 



3 %* 



3.65 



2.86 



2.68 



Wesmnshouse 
A/A-/ 



7 CAR 



8 C & R 



4J6 



3.24 



3.06 



Sess/o/vs 
K 



1/ 



1/2 <% R 



4.37 



3.62 



3.8/ 



Sess/oass 
Jumbo 



14 C § R 



WW? 



4.30 



3J8 



3.26 



Cardwell 
S-2S-A 



W car 



'd 



C 1 R 



4.05 



2.9/ 



297 



Cardwell 
6-/8-A 



WW 



v 



CAR 
A 



3.85 



260 



2.79 



M/NER 

A-/8S 



23 c i 



CAR 



24 CAR 



4.46 



3.74 



3.57 



A1/NER 

A-2S 



2G 



CAR 



zft 



27 '<%* 



3.2/ 



2.62 



247 



Nat/on a l 



29 c % 



CAR 



$0 C £ R 



5.07 



318 



3.95 



Nat/on a l 
A4-/ 



\32 c i R 



W^¥ 



4.26 



3.36 



3.08 



Nat/onal 
M-4 



35% 



CAR 



4/2 



3.24 



3.33 



Murray 
/i-28 



38 c i' 



CAR 



39 C 4 R 



3.45 



259 



2.76 



Gould 
/75 




356 



263 



2.72 



Bradford 46 



K 



W c i R 



2.78 



2.28 



2.04 



Waugh 
Plate: 



3.02 



2.23 



/S4 



Crrasty 



3.73 



3.37 



3.56 



Harvey 
2-8'k8"spRGs. 



55 c § 



CAR 



rSPRGS.56^ R 

Srr/a/gs 58 c j R 



233 



/.64 



/37 



O/L 

2-8x8°clas$g 



/84 



/3/- 



/.45 



Fig. 65 — Comparison of Double Gear and 

Single Gear Action. Car-Impact Tests. 

143,000-lb. Cars. 



COMPARISON OF THE DIFFERENT METHODS OF TESTING 



A study of the performance of the in- 
dividual gears throughout the several dif- 
ferent tests can be best made from the 
tables of Figs. 17 and 66. In most gears a 
wide difference appears between the static 
test results and the dynamic results, but in 
general there is not a wide difference be- 
tween the drop test results and those in the 
car-impact tests. Static tests in general are 
usually made to determine the ultimate re- 
sistance of the gear, and the work done 
and work absorbed. It has generally been 
supposed that the character of the com- 
pression line was indicated by the static 
tests. These present tests show that the 
static test is not a measure, either absolute 
or comparative, of work done, work ab- 
sorbed or ultimate resistance. For example, 
in the static test the Westinghouse D-3 
gears averaged 18,550 ft. lb. of work done, 
while in the drop test the average work 
done was 15,375 ft. lb., the static capacity 
being 12 per cent higher than the drop 
capacity. On the other hand, in the Na- 
tional M-l gear the static result is 263 per 
cent higher than that of the drop test. No 
uniformity whatsoever obtains in this per- 
centage. 

An interesting example of static test- 
ing is in the case of two of the National 
H-l gears tested after three years' service 
on the Norfolk & Western Railroad. These 
two particular gears were first tested in the 
static machine and showed an ultimate re- 
sistance of 296,000 lb. and 392,000 lb. 
respectively. The gears were then drop 
tested and the total fall of the 9,000 lb. 
weight required to close them was 17y 2 in. 
and 16y 2 in. respectively. The building-up 
test was then made under the 9,000 lb. drop 
and after an average of 21 blows per gear 
the total fall had increased to 29i/ 2 in - an( l 



241/2 in. respectively. The gears were then 
retested in the static machine and showed 
an ultimate resistance of 112,000 lb. and 
104,000 lb. respectively. All of these tests 
were made in a short period of time and 
under identical conditions. They show 
most clearly the erratic nature of the static 
tests. It is found in general, however, that 
the line of static compression follows the 
characteristics of the line of dynamic ac- 
tion, and that the ultimate resistance in the 
two tests are closely proportional to the 
work done in the tests. 

With some few exceptions, the drop test 
results, as to capacity and absorption, show 
a fairly uniform relationship to the car- 
impact results, the latter in general being 
from 5 per cent to 20 per cent higher than 
the drop test results. The drop test accord- 
ingly would appear to be a fair compara- 
tive measure of draft gears for capacity 
and absorption. The table, Fig. 66, shows 
the average capacity results from the gears 
in the different tests, the quantities being 
the average of those actually obtained for 
the two gears of- a type used in the car- 
impact tests. 

The following general conclusions are 
drawn from a comparison of the action of 
the gears throughout the different tests: 

1. That the speed of static testing within 
the limits of the average testing machine 
has in general but little influence upon the 
ultimate resistance of the gear. 

2. That gears of a type may vary great- 
ly in the static test and at the same time be 
of approximately equal capacity under the 
drop. 

3. That the static capacity of a gear is 
no indication whatsoever of its dynamic 
capacity. 



— 129 



130 



Draft Gear Tests of the U. S. Railroad Administration 



4. That in general, friction gears show 
greater capacity and higher ultimate re- 
sistance in the static test than in any other 
test. 

5. That the ratio of ultimate resistance 
to work done varies but slightly as between 
different gears of the same type in the static 
test. 

6. That the ultimate resistance in the 
static test and in the car-impact test is in 
general closely proportional to the work 
done by the gear in these two tests. 

7. That the ultimate resistance in the 
car-impact test and the computed ultimate 
resistance in the drop test (Column 10, Fig. 
17) are in reasonably close proportion to 
the relative amounts of work done by the 
gear in these two tests. 

8. That in the majority of cases the 
static curve shows the characteristics of the 
dynamic action of the gear, but that it is 
not a true measure of its dynamic capacity 
or ultimate resistance. 

9. That the drop test, with a single gear 
supported upon the solid anvil, is in gen- 
eral a fair comparative test of gears as to 
dynamic capacity. 

10. That the car-impact results will in 
general be greater than the drop test re- 
sults by from 10 per cent to 20 per cent. 

11. That the relative recoil of gears may 
be satisfactorily measured under the 9,000 
lb. drop. 

12. That neither the drop test, the static 
test, nor any other test using inelastic 
means for closing the gear will disclose 
roughness or irregularity of gear action: 
That tests upon a resilient body such as a 
standard car will alone disclose this fea- 
ture of gear action. 

The car-impact tests themselves have 
established and confirmed numerous prin- 
ciples of gear and car action, among which 
may be noted: 

1. The relative merits of the different 
methods of draft gear testing. 



2. The exact impact velocities at which 
the various gears will cease to offer further 
protection to the cars. 

•3. The production of complete dynamic 
cards of gear action. 

4. The independent and inharmonious 
action of gears when dynamically closed in 
opposition to each other. 

5. That gear action and car action in 
practice are not smooth and regular, even 
with the best friction gears. 

6. That a friction gear is necessary for 
obtaining capacity and for eliminating 
recoil. 

7. That the yield of the car structure and 
the lading do not afford any material aid 
in the dissipation of energy, and that fric- 
tion draft gears in modern cars are essen- 
tial to avoid high forces and early failure 
of parts. 

8. That preliminary spring action shows 
no especial value in buffing and that heavy 
initial gear compression is not disadvanta- 
geous. 

9. That the force developed between cars 
in buffing is due to the inertia of the cars, 
and when the slack is not bunched is the 
same whether the struck car be standing 
alone or whether it be at the head of a 
draft of cars; that the force is practically 
the same whether the struck car be standing 
with or without the brakes set. 

10. That there is a positive displacement 
of the center sills relative to the side sills 
of a car, the amount of which is dependent 
upon the character of the construction 
tying these members together. 

11. That in a modern steel car, a force 
equal to the ultimate resistance of the high- 
est capacity gear in these tests will be de- 
veloped between cars, without draft gears, 
at an impact velocity of iy 2 miles per 
hour. 

12. That if a gear is properly con- 
structed as to sturdiness it requires but a 
slight over-solid speed to produce a high 



Draft Gear Tests of the U. S* Railroad Administration 



131 



*3a 


Average Work Done 
Per Gear. Ft LBs. 


average Work Absorbed 
Per Gear. Ft. Lbs. 


/n 

STAT/CC 
TEST 


i/v 

PROP 
TEST 


IN 
CAR 
IMPACT 
TEST 


in 

STATIC 
TEST 


/N 

DROR 

TEST 


/N 
CAR 
/MPACT 
TEST 


© 


© 


® 


© 


® 


® 


© 


WEST/N6WUSL 

D-3 


/8S50 


/537S 


74667 


/6467 

88.7% 


Z2533 

8/6% 


Z2Z67 

83.0% 


W6ST/N$WUS£ 

ZVA-Z 




/7250 


79/67 




Z47/2 

85.4% 


Z67/7 

37.2% 


Sess/ons 


34700 


Z4245 


79367 


32400 

93.4% 


///64 
78.4% 


Z637S 

84.5% 


UUMBO 


47/35 


2/773 


79025 


42725 

90.GX 


/7460 

80.3% 


Z43Z7 

750% 


Cardwell 
6-25-A 


49550 


/S563 


Z79/7 


475/7 

36.0% 


Z3298 

85.4% 


Z5554 

86.6% 


Cardwell 
G-/8-A 


26250 


Z4453 


777/7 


25000 

35.2% 


/3500 

93.5% 


75575 

30.9% 


M/NER 

A-/8S 


4/084 


75769 


787/7 


584/7 

93.5% 


Z2244 

77.7% 


Z3334 

7/3 X 


M/NER 

A-2S 


54667 


3762 


70025 


35/67 

35.9% 


6908 

70.3 % 


8477 

83.8% 


Nat/onal 
H-/ 




23250 


27/84 




Z3962 

85.7% 


20750 

76.3% 


Nat/onal 
M-/ 


53/00 


74648 


20000 


50267 

34.7% 


/2087 

82.5% 


'76784 

840% 


Nat/onal 
M-4 


3/465 


/6872 


Z8467 


29234 

33.0% 


Z4337 

85.0% 


Z58Z7 

85.8" 


Murray 
H-2S 


Z8/34 


Z2466 


Z3900 


/6250 

89.6% 


/0002 

80.3% 


ZZ584 

83.3% 


Gould 
Z75 


20/84 


73478 


73767 


/70S0 

84.6% 


8/42 

60.4% 


zozoo 

73.5% 


Bradford 
K 


6409 


7830 


6833 


/708 

26.7% 


4340 

55.5% 


2Z50 

3/4% 


Waugh 
Plate 


8600 


/03/3 


9/00 


44/7 

5/4% 


45/2 

43.8% 


4ZZ7 

45.2% 


Chr/^sty 




16684 


Z2934 




Z2623 

75.7% 


Z09/S 

84.4% 


Harvey 
2-8x8"5fgs. 


3034 


7722 


4992 


4767 

52.8% 


4448 

575% 


2709 

54.0% 


Co/lSfr/a/gs 

Wx8 CLASS G 


3800 


4279 


4ZZ7 


43.4 
//4% a 


Z208 

28.2% 


450 

ZO.9% 



Fig. 66 — Comparison of Work Done and Work Absorbed by Test Gears in 
Static, Drop and Car-Impact Tests 



132 



Draft Gear Tests of the U. S. Railroad Administration 



force peak; conversely, if a gear is not 
sturdily constructed an over-solid blow 
may never produce a high force peak, but 
such over-solid blows will quickly deterio- 
rate the gear, and so reduce its efficiency 
that low impact speeds will cause damage 
to the car.' 

13. That the average period of draft gear 
compression with a friction draft gear is 
equal to approximately 1/3 of the entire 
cycle of impact and that the release occu- 
pies approximately 2/3 of the cycle. The 
maximum period of impact experienced 
was approximately y 2 second. 

14. That with a spring draft gear the 
period of compression and of release are 
approximately equal and that the spring 
returns practically all of the energy, bring- 
ing the striking car to complete rest and 
imparting almost the original velocity of 
impact to the struck car. 

15. That several acceptable draft gears 
are now available capable of protecting a 
57i/2-ton car up to a switching speed of 
4 M.P.H. Furthermore, that there is not 
an occasion for higher switching speeds 
than 4 M.P.H. 

General Deductions 

From the tests as a whole the following 
general deductions can now be made and 
are recommended by the Inspection and 
Test Section of the United States Railroad 
Administration: 

1. That for use on any car a gear should 
be selected which will not go solid at less 
than 31/2 M.P.H. nor more than 4% M. 
P.H. when the weight of the particular 
car to which it is to be applied is con- 
sidered together with the complete informa- 
tion given in this report. 

2. That there is no advantage in buffing 
from preliminary spring action, and that 
a draft gear should preferably be under 
some initial friction compression; not only 



for the increased capacity effected, but 
also to hold the friction elements in posi- 
tive engagement at all times, in order to 
provide a greater latitude of wear and to 
prevent the deposit of foreign material 
upon the friction surfaces. 

3. That draft gears should have an effec- 
tive area for receiving over-solid blows 
slightly greater in extent than the area of 
the coupler shank; that this area should be 
presented in direct line with the force and 
should preferably be relieved of all other 
draft gear forces. 

4. That all gear units should be of in- 
terchangeable dimensions and of equal 
travel. That considering the results of the 
high capacity Miner and National gears of 
2y 2 in. travel, both in new condition and 
after prolonged service, together with the 
results from the Westinghouse NA-1 gear 
which is also of high capacity and of 3 in. 
travel, it is believed that the maximum 
travel figure of 2% in., as set by the Com- 
mittee on Standards of the United States 
Railroad Administration, might well be set 
as a fixed and required standard travel for 
all new gears. 

5. That from this standpoint of satis- 
factory operation there is no reason why a 
draft gear of 2% in. travel should not be 
designed with an ultimate dynamic resist- 
ance of 500,000 lb., provided the rate of 
increase of resistance is uniform through- 
out the travel of the gear. 

6. That no gear should be of a greater 
capacity at this travel than will close at an 
impact velocity of 5 M.P.H., with 57%- 
ton cars, or show a greater drop test ca- 
pacity than 25,000 ft. lb. Such a gear 
will close in a 120-ton car at 3% M.P.H. 

7. That the expression, "a draft gear of 
150,000 lb. capacity," is erroneous and 
should not be used ; and that the % in. rivet 
shearing test as used to define the above 
expression should be abandoned in favor 



Draft Gear Tests of the U. S. Railroad Administration 133 

of regular 9,000 lb. drop tests, or prefer- tion, Section 3, should provide itself, with 

ably car-impact tests, until such time as a a gravity car testing plant of the general 

more convenient test for smoothness of character of that used for these tests, 

gear action can be developed. whereupon to conduct such draft gear and 

8. That the American Railroad Associa- car construction tests as may be desired. 



RESULTS TO BE EXPECTED FROM COMMERCIAL GEARS 



The table, Fig. 67, has been prepared to 
show in condensed form the average re- 
sults that may be expected from new com- 
mercial gears of the different types. This 
tabulation embraces all of the different tests 
and the results in general are based upon 
the average performance of all of the gears 
of a type in the tests. This tabulation may 
be used as the basis for any comparisons 
desired of average gears. 

In Fig. 68 are shown energy curves for 
cars of different weights, the rotative en- 
ergy or fly-wheel effect of the wheels and 
axles, which amounts to an addition of ap- 
proximately 3 per cent, being included. 
Horizontal lines representing the closing 
points of the various gears have been lo- 
cated on this diagram so that the value of 
any gear upon cars of the different weights 
may be readily obtained. These horizontal 
lines for the several gears are based upon 
the action of the average commercial gear. 
By means of this diagram the application 
of the results may be readily converted 
from a specific case to general cases. 

In considering the cushioning value or 
closing speed of a gear it should be remem- 
bered that the kinetic energy of the striking 
car should be equal to approximately four 
times the energy required to close one draft 
gear. 

The present report contains much in- 
formation deduced from the car-impact 
tests relating to draft gear functioning such 
as, time of gear cycle, vibrations in car 
bodies, travel of cars along the track dur- 
ing the several portions of the gear cycle, 
instantaneous car velocities, transition and 
absorption of energy, forces developed, 
comparison of dynamic and static work dia- 
grams, car body absorption and other gear 
characteristics. This is given, in general, 



for the closing runs with the single gears 
and for the 1 M.P.H. runs and the closing 
runs with the double gears. A wide range 
of further draft gear information is ob- 
tainable from these tests, especially from 
the intermediate runs made upon each gear 
and particularly from those just slightly 
below the closing point. As a specific ex- 
ample of what may be done in this respect, 
the intermediate runs have been worked up 
for the Westinghouse D-3 gear and sum- 
mary curves have been developed. These 
are shown in Fig. 89, where can be seen 
for various impact velocities: 

(a) The velocities of the cars at parting. 

(b) The coefficient of restitution. 

(c) The energy absorption. 

(d) The absorption efficiency. 

(e) The track movement of the cars. 

(f) The force developed between the 
cars. 

(g) The time of the draft gear cycle. 
(h) The amount of gear closure. 

The same factors are also expressed in 
terms of gear closure instead of impact ve- 
locities in curves j to q inclusive of this 
same figure. 

Lack of time has prevented an analysis 
of all of the gears in this manner, as the 
immediate effort has been to present suffi- 
cient information for each of the several 
gears to properly compare and grade them. 
It is hoped to make further studies of an 
analytical character from these tests, the 
results to be published when completed. 
From such studies can be established and 
verified many of the fundamental laws of 
draft gears which are at present unde- 
veloped. From the present test data also 
such studies can be made as: the coeffi- 



134 — 



Draft Gear Tests of the U. S. Railroad Administration 



135 



cient of friction under a wide range of con- 
ditions, such as various materials, unit pres- 
sures and relative velocities of one friction 
face upon the other; the effect of various 
spring and friction relationships; angu- 
larity of friction faces, etc. In short any 



further work should be the development of 
the intermediate runs, the production of 
summary curves, a study of the funda- 
mentals of gear construction, and the for- 
mulation therefrom of mathematical laws 
of draft gear action. 



136 



Draft Gear Tests of the U. S. Railroad Administration 



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138 Draft Gear Tests of the U. S. Railroad Administration 




' 2 3 4 S G 

M/LES /=>F/? HOUR. 

Fig. 68 — Energy Curves for Cars of Various Weights, with Commercial Gear Capacities 

Indicated 



GRADING OF AVERAGE COMMERCIAL GEARS 



Any one familiar with draft gear oper- 
ation and testing can from the foregoing 
results, and particularly from table Fig. 
66, establish his own rating of the gears. 
The relative total merits of the types will 
differ, depending upon the importance at- 
tached to the several features of gear ac- 
tion. No one gear excells in all points. One 
represents the highest capacity ; another the 
highest percentage of absorption; another 
the highest degree of smoothness of action. 
The tabulation, Fig. 69, has been pre- 
pared on the basis of the following rela- 
tive weights or percentages for the several 
phases of gear performance: 

Capacity 50 points 

Smoothness of action 15 points 

Closing pressure 5 points 

Absorption 15 points 

Over-solid sturdiness 10 points 

Workmanship and General 

operation 5 points 

Total 100 points 

The gradings on the above basis are made 
directly from the test results, except for 
the last item of 5 points which represents 
those features that it is impossible to de- 
note in abstract figures. 

Capacity 

In setting percentages as above, gear ca- 
pacity is unquestionably the prime meas- 
ure. A gear might excell in all other 
points and yet properly belong at the bot- 
tom of the list because of an extremely low 
closing speed. After a gear is closed it 
becomes a question of metal to metal for 
the remainder of the blow, hence the im- 
portance of continued gear action at higher 
impact velocities. The grading of the gears 
as to the capacity is based upon the square 
of the closing speed of the commercial 
gear. 



Smoothness of Action 

After capacity, the next feature is 
smoothness of gear and car action. With 
equal capacities, that gear is the best that 
will start off the struck car with the least 
disturbance and vibration of the car struc- 
ture and the least shifting of the lading. But 
it is not to be expected that a gear capable 
of cushioning the blow up to five miles per 
hour will ease off the cars at its high clos- 
ing speed like a 2 M.P.H. gear at its lower 
closing speed. The first gear is doing six 
times the work of the second gear and doing 
it in the same limited distance, hence more 
disturbance is to be expected with this gear 
at 5 M.P.H. than with the light gear at 
2 M.P.H. The grading of the gears for 
smoothness of action is based upon the 
relative smoothness of the velocity curves 
in the closing runs, with the square of the 
actual impact velocity of the run introduced 
as a factor. 

Ultimate Force or Closing Pressure 

All other things, and particularly ca- 
pacity, being equal, the gear that puts the 
least force into the sills at the closing point 
of the gear is entitled to a credit. This is, 
however, largely allowed for in the pre- 
ceding grading of smoothness of gear ac- 
tion, inasmuch as the lower and more regu- 
lar force will produce the smoothest ve- 
locity curves. The closing force of a gear, 
furthermore, is largely governed by the 
amount of travel of the gear. But in order 
that those gears that have a dynamic card 
of decidedly full area may have credit, a 
weight of five points has been allowed in 
addition to the previous allowance of 15 
points for smoothness of car action. The 
ratings for the several gears in this respect 
are not based directly upon the closing 



— 139 — 



140 



Draft Gear Tests of the U. S. Railroad Administration 



pressure of the gear, as it could not be ex- 
pected that a 5 M.P.H. gear should close 
at the same ultimate force as a 2 M.P.H. 
gear. The grading in this respect is based 
upon the ultimate force per foot pound of 
closing capacity. 

Absorption 
While energy absorption, contrary to a 
popular understanding, does not in any 
manner reduce or absorb the force between 
two colliding cars, it is of importance as 
indicating whether the force between the 
second and third cars will be the same, due 
to high recoil of the gears and rebound of 
the cars, or whether the energy of closure 
will be partly absorbed. These gradings 
are made on the basis of percentage of ab- 
sorption instead of absolute absorption, as 
a certain amount of recoil is necessary for 
parting of trains and to insure gear re- 
lease, the amount of which varies accord- 
ing to the capacities of the gears. A gear 
with too high a percentage of absorption 
is likely to stick, especially in train service. 
The higher the gear capacity the more foot- 
pounds of energy are needed to insure its 
release. Hence the percentage of absorp- 
tion is undoubtedly the fair basis of grad- 
ing in this respect. In allowing 15 points 
for absorption it has been borne in mind 
that the capacity grading alone takes care 
of absorption in a large measure, for high 
capacity is impossible except by means of 
friction, and the introduction of friction at 
once produces absorption. Hence any gear 
of high capacity has necessarily a high 
amount of absorption. 

Over-Solid Sturdiness 
It is highly important that gears be sturdy 
enough to withstand reasonable over-solid 
impacts. For a good showing in over- 
solid laboratory testing, it is desirable to 
have a weakly constructed gear, but for en- 
durance and life in service it is necessary 
to have sturdy parts to receive the solid 
blows. The grading in this report is based 



upon the number of over-solid blows re- 
quired to produce visible gear failure. 

Workmanship and General Operation 
Under the title of workmanship and gen- 
eral operation are included not only the 
finished and workmanlike manner in which 
the gears are constructed but those facts 
and impressions which have been gained 
during the progress of the test. Certain 
gears are finished articles throughout, well 
designed mechanically and exhibiting care- 
ful and accurate manufacturing practices. 
Other gears are carelessly produced and 
put together with apparently no thought 
as to the accurate relationship of the vari- 
ous parts. Some gears failed in certain de- 
tails before reaching the solid point in the 
test. Other gears stood extreme punishment 
without failure. Five points only have been 
allowed to cover this large variation be- 
tween the greatest and the least excellence, 
and it is conceded that this is not enough 
to represent these differences. The reason 
that five points only was chosen is be- 
cause this one item of workmanship and 
general operation is to a degree a matter 
of opinion on the part of the testing en- 
gineer, and the element of personal opin- 
ion is thereby reduced to a minimum. 

Service Performance of Gears 
It is recognized that the service perform- 
ance of the gears is one of the most im- 
portant considerations, but in the absence 
of positive and uniform service tests for 
all gears no grading has been made in this 
respect. Some notes on service tests and 
service testing appear hereafter. 

State of Development of Gears 
It is recognized also that those gears are 
entitled to credit which have been under de- 
velopment and in use for a longer period 
of time. This factor cannot be reduced to 
abstract figures, but can be best judged by 
the history of any particular type of gear 
on the specific railroad. 



Draft Gear Tests of the U. S. Railroad Administration 



141 



2 
O 

5 S 


MAKE ANO 
TYPE OF 
GEAR. 


£5 


ie 

O m 


111 " *' 


00 " 
< 


a? 


«i ec r r 
tf z * - 

IS 


TOTAL 





© 


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-5 

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National 
HI 


50 


7 


3 


12 


10 


5 


87 


































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a: 

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■ofi 

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36 


15 


4 


15 


3 


5 


78 


Miner 
A-18-5 


38 


8 


3 


13 


6 


5 


73 


Nat/onal 
Ml 


36 


9 


3 


13 


7 


5 


73 


NATIONAL 

M4 


35 


8 


5 


14 


5 


5 


72 


SESSIONS 
J UMBO 


36 


9 


4 


13 


3 


4 


69 


Sessions 
K 


38 


2 


4 


13 


1 


2 


60 


































* 


a.- 


CAR DWELL 
6-2S-A 


30 


II 


4 


15 


2 


3 


65 


CARDWELL 
G-I8-A 


30 


9 


4 


15 


2 


4 


64 


W£ST>M&H0VJ£ 


25 


II 


4 


14 


3 


5 


62 


MURRAY 
K-25 


25 


IO 


4 


14 


3 


4 


60 


MINER 
A- 2-5 


21 


IO 


5 


14 


5 


3 


60 


Gould 
17,5 


25 


8 


3 


12 


3 


4 


35 


CHRISTY 


24 


5 


4 


14 


6 


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PLATE 


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44 


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33 


Bradford 
K 


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7 


2 


5 


1 


1 


32 


Coil SPRiw&j 
2-ARA- CLASS G 


7 


4 


3 


2 


2 


5 


23 


(A word of caution is necessary in using this table. While in most cases the 
statement is made in the chapter on "Selection and Condition of Test Gears," 
page 24, that the results of the tests are believed to be representative of the 
action of the commercial product, certain exceptions are noted, namely: 
Cardwell G-25-A, Murray H-25, Bradford K and Christy. — Editor.) 



Fig. 69— Grading of Gears, Based Upon Performance of New Commercial 

Gears 



SERVICE TESTS 



It has not been possible during the per- 
iod of the present test work to begin the 
comprehensive series of service tests de- 
sired. It has been planned to equip not 
less than 20 cars with each type of gear 
in these tests and to run all of the cars in 
the same restricted service so that uniform 
treatment may be accorded each type of 
gear. The gears are to be inspected, meas- 
ured, and drop tested before application 
to the cars and are to be kept under con- 
tinual observation. Ten cars with each 
type of gear to have Farlow draft gear at- 
tachment and ten to have yoke and lug at- 
tachments. Five cars in turn with each 
type of attachment are to have the draft 
gear protected by allowing the coupler 
horn or the Farlow middle key to strike. 
The remaining five, with each type of at- 
tachments are to have the full load de- 
livered to the sills through the draft gear. 
The condition of the gears, attachments and 
cars is to be reported each year and all 
gears are to be removed for laboratory 
tests after two years of service. Those 
worthy of further testing are to be con- 
tinued in the test for an additional period 
of two years. It is only in such a careful 
and comprehensive test that reliable serv- 
ice information can be obtained. 

A similar service test embracing five 
types of gears has been under way on the 
Norfolk & Western Railway for approxi- 
mately four years. The United States 
Railroad Administration Inspection and 
Test Section was thereby afforded an op- 
portunity to observe the service action of 
test gears of several different types. In 
the Norfolk & Western tests the National 
H-l and Miner A-18 gears showed the 
least percentage of depreciation. Gears 



representative of the average condition of 
these two types, after three years of service 
on Norfolk & Western 100-ton coal cars 
in restricted tide-water-service and aver- 
aging at least 50 miles per day, were given 
car-impact tests by this Section. A num- 
ber of gears of each type in the Norfolk 
& Western test had been removed and 
tested under the 9,000 lb. drop. These had 
been carefully handled from the cars to. 
the testing machine and the closing point 
was determined in as few blows as pos- 
sible without disturbing the foreign ma- 
terial upon the friction surfaces. Two 
average gears of the National H-l and the 
Miner A-18 were also taken to the car- 
impact test plant at Rochester and tested in 
the same condition as to friction surfaces. 
The worn Miner gears closed at an impact 
speed of 3.48 M.P.H. and the National at 
4.21 M.P.H. The capacity of the Na- 
tional gears averaged 21,000 ft. lb. and 
the Miner 14,200 ft. lb. The gear action 
and cushioning were good in both instances 
and the actual capacity of these gears and 
the protection being afforded the cars after 
such a period of service is unexpectedly 
high. 

The table, Fig. 37, shows the aver- 
age condition of the several gears in the 
Norfolk & Western tests, and shows by 
means of the drop test, what each type is 
actually doing in service. The table shows 
also, by means of the restoration test re- 
sults, what portion of the depreciation is 
probably due to wear and what to foreign 
material upon the friction surfaces. These 
service tests were made in a careful and 
exact manner and with uniform conditions 
for all gears. 



— 142 



TRAIN-OPERATION TESTS 



It is desirable to make a series of train- 
operation tests of draft gears before fully 
determining upon ideal gear characteris- 
tics. But a complete mathematical an- 
alysis of the car-impact data contained in 
this report should be made before begin- 
ning such road tests. All of the necessary 
information is at hand in these present re- 
sults for the accurate calculation and de- 
termination of the ideal gear for train 
starting and handling as well as in yard 
service. After such analysis is made a 
rational program of train tests can then 
be formed for confirming the calculated 
results. This method will not only insure 
a test program directed straight to the 
ends sought but will also obviate many un- 



necessary tests that would otherwise be 
made in searching for the desired informa- 
tion. 

In connection with the Norfolk & 
Western service tests an opportunity was 
presented for obtaining some limited in- 
formation as to the action of draft gears in 
actual train service. In this test, adjoining 
cars were equipped with gears of differ- 
ent capacities and characteristics, and by 
means of chronographs, each gear was 
caused to draw a continuous line of gear 
action upon a moving ribbon of paper. 
The report of this test, dated November 4, 
1918, is appended to the present draft gear 
report as a matter of general information 
and record. (See Appendix A.) 



TESTS OF DRAFT GEAR ATTACHMENTS 



While testing draft gears, the opportunity 
was presented for making car-impact tests 
of draft gear attachments. Two 70-ton 
United States Railroad Administration low 
side gondolas were equipped with Farlow 
two-key draft gear attachments and tested 



in comparison with United States Railroad 
Administration standard cast steel yoke and 
lug attachments. A full report of this test, 
together with tests of wood car construction 
with and without metal draft arms, is at- 
tached to this report as Appendix B. 



10 



143 — 



144 Draft Gear Tests of the U. 5. Railroad Administration 



MAKE AMD 

TYPE OF 
GEAR 


Car-Movement 
Curves 


Velocity 
Curves 


Energy 
Curves 


Time - Force 

Curves 


Tir\AE- Closure 
Curves 


Force -Closure 
Curves 


Ui*S 


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H-l 


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A-E-S 


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Fig. 70 — List of and Index 



of Car-Movement 
71 (a to t) to i 



Curves and Derivative Curves, Embracing Figures 
8 (a to t) Inclusive 



Draft Gear Tests of the U. S. Railroad Administration 145 




77me — Seconds 

Fig. 71a — Car-Movement Curves, Superimposed. National H-l Gears. These Curves Drawn 

by Cars in Test 



146 



Draft Gear Tests of the U. 5. Railroad Administration 



~i ' — ^ — J 

Test- Gear A/a JO in Car A 
Test Gear No.29in Car 3 

■i : 1 — — <— 



Nomina/ /rrpac-f Velocity /ftif?H 




77me — Seconds 



Figs. 71b and 71c— Car-Movement Curves, Superimposed. National H-l Gears 
These Curves Drawn by Cars in Tests 



Draft Gear Tests of the U. S. Railroad Administration 



147 



i 







So//d Buffer /n Cor A. 
Test Geor No. 29 /r? Cor 3. 
fmpoct Vefoc/ty=3 .95 MPH 



-30 



figure 
7fcf 



40 



.15 20 .25 
0/68 Sec. Geor Fe/eose 



0.26O Sec. Draff Geor Cyc/e 



lest Geor No. 30 fn Cor A. 
Test Geor No. 29 fn Cor 3. 
fmpoct Ve/oc/fVf/./<4 Mm 



10 Ft per sec. 



*-Q40 Ft per sec. 



figure 
7/e 



.30 



.35 



40 



45 



fest Geor No. 30 /n 
Test Geor No. 29 In 
Impact \Ze/oc/7y=S.0t 



&~A 

0r& 

mm 




-0.246 Sec. Draft Geor Cyc* 

Time Seconds 



Dotted lines represent instantaneous car velocities as 
determined from the original car-movement curves. 



The irregularities are due in general to vibrations of the 
car structure induced by draft gear action. 
Full lines represent mean velocity curves. 



Figs. 71d, 71e and 71f — Velocity Curves, National H-l Gears 



148 Draft Gear Tests of the U. S. Railroad Administration 




.45 



120 


^26,300 n 


u Lbs. 








7est Gear A/a 30 in Car A 

7es+ Gear Ah. 29 /h Car B 

//npacr l/e/oc/fv =.&. 07 M.RH 


























CorA^ 




















SO 












<-67.200Frt 


jbs. 








60 
































-j/.&ortiA 


?. 














20 


Cor B-%^ 














s. 










20 
40 
60 

80 










\ 






















\ 


\ 






















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—5t46/FtL 

WorkAbsor 


As. 
bed. 










A 


v- 


63,860 Ft L 
Work Done 


bs. 










Figure 






06 


/O J5 .20 c 
., p ,ir* •Sec. Gear- Re/ease 1 


i5 .30 .35 .40 <4\ 


5 




ao9/ Compression 

- c a. 


^< 


t r- Soc Drx 


?fr Gear 


Cycts. J 





Full lines represent the instantaneous kinetic energy of the 
moving cars. 

Figs. 71g and 71j — Energy Curves, National H-l Gears 



Dotted lines represent the energy stored and absorbed 
during the draft gear cycle. 



Draft Gear Tests of the U. S. Railroad Administration 



149 



A)0 












ootid 'Buffer //? Cor A. 
lest Gear No. 29 //? Car 3. 
frnpocf Ve/oc/ty=395 M.P/i. 




bOO 




















• 


500 






















400 






















500 






















200 
























ZOO 






















f/gure 
7/k 





.05 
—0.06/ - 


JO /S 
- Of/0 ^ 


2 


.25 30 .35 .40 45 



. -Sec. Gear Re/ease 
h O./W Sec. Draft Gear Cyc/e\— 



200\ 




■ Sec. Gear Compress 

I— 0246 Sec Draft Gear Cyc/e 

T/me — Seconals 
Figs. 71k and 71m— Time-Force Curves, National H-l Gears 



150 



Draft Gear Tests of the J/. 5. Railroad Administration 



6 












Soiid Buffer in Cor A 

lesf Gear No. 29 in Car 3 

impacf Veiocifv=3.3SM.PH. 


■4 

3 




















C^/ 




















2 
/ 




<^> 


/j 








































figure 
7in 




.05 
-o/V-/Sec. Gear 


JO V5 
. * ,, n Sec Gear- /?e/ease^ 


.20 .25 .30- 35 .40 .45 




^^'Compre 
- 0/ 


ji Sec. Drcrfj- Gear Cyc/e^ 


















lesf Gear No. 30 in Car A 

lesf Gear No. 29 in Car 3 

impacf Veiocifv — i.20 M.PH 
























































.0 


5 ./( 


1 ./, 


5 .2 


.2 


5 .a 


.35 .40 .45 



0.092 



Compress/on 



Sec. Gear Re/ease. 



Q26Q 



OJS8 
Sec. Draff- Gear 



Cycle 



7 
6 
5 












lesf Gear No. 30 in Car A 

lesf Gear No. 29 in Car 3 

impacf Veiocifv — S.Q7 M.RH 




D 




















/' 


















3 
2 




























_ a 














f B jf 


yV 






^r 












1 






P* 








s- 










Figure 




O 

^osi£^ t 


5 
Sear 


./O .15 .2 

m *,r* Sec. Gear- / 


J25 .30 .35 .^O .45 
Release. 




'ss/on. 
C 


3 


f^ Sec. Ore 


ft Gear 



Wme — Seconds 



Curve D, determined from superimposed car-movement 
curves, represents combined draft gear movement and yield 
of car bodies. 

Curve C, obtained by eliminating car body yield from 
curve D, represents true combined movement of both gears. 



Curve B, traced on small drum, represents movement of 
gear in Car B. 

Curve A, derived from curves C and B, represents simul- 
taneous movement of gear in Car A. 



Figs. 71n and 71q— Time-Closure Curves, National H-l Gears 



Draft Gear Tests of the U. 5. Railroad Administration 151 



600 


1 260- 











5o//of Buffer In Car A. 




500 


Test Gear Na r 29 tn Car B, 






Impact 


'e/oc/ty=3.95 / 


tPH 420,000 


» 


400 




























300 


























% *o 














"ft Wi 














r 










^ '/ 


'ygure 


I 












7/r 


£ < 


i 


/ 




1 


> 


3 



I 



Gear C/osure —/nct?es 



9VL 












1 2.46 — 






Test Gear /Vo. 30 //? Car A. 






80& 




Test Gear No. 29 /n Car 3. ! 










f/r?pact\ Ve/oc/ty=5.07 MPH. \ 






700 
















60& 






















Gear C 
S50.0L 


Jasecf i 
?0*~~~A 






















500 










1 


(7<?(7/- : Case*/ 
/ 390.000* 












Stf 


( » 


400 










«ti 


■ -£«o 


30C 












^ 










/ J 


<8° 












C »'' 


; 




200 










'7 ! 






100 








SS- r 








^— ii« 








• 


^ 


figure 









— <— ■■« 


« *'" 






7/t 







/ 


i 


2 




o 





JU(/ 












fes/" ^ia7/- /V6J0 /^7 Cor A. 


800 


Test Gear No. 29 //? GprD. 




/mpoct, l/e/od 


ty=/.20M.PH 


700 










$600 
SJ 




















' 






§<500 




























$$300 


















1 










^ 
^ 













Gear C/osure— foc/ies 



/ 2 

Gear Closure— /r?cf?es 



Fics. 71r and 71t— Force-Closure Diacrams, National H-l Gears 



152 Draft Gear Tests of the U. S. Railroad Administration 



3 
<3 

r 






So//d Buffer /n Car >< 
Test- Sear Ad.// in Car 3 














C/c 


s/ng Sp 6 


>ed 












Car B — 
2.64 W/?M 




sS*/./2M./?H. 










i 

r 

2 

r 














C3 

1 


hjr 




>3 

J! 


















c$S 




(0 

b 


* 
















A 




O 


(3 
5 














| 


S 










1 
















f 








< 


vl 
5 










/,,,.,— -*"^! 


i i 


















figure 
7ea 


d 


OS 
5"«>c 6isw 


^ 




Sec. Gear^ Re/ease. 


20 25 30 .35 .-40 .45 


4 


Compression. 


a£> 


•c. DrcrPf Geo/" C\yc/e. 

















Fig. 72a — Car-Movement Curves, Superimposed. Sessions K Gears. 
These Curves Drawn by Cars in Test 



Draft Gear Tests of the U. S. Railroad Administration 



153 




TTme — Seconds. 



r 

u 

I 








Te^y- Gear No./2/n Car A 
Tes-r Gear No.// tn CarB 














ao 


sing Spe 


ed 


Can e 
£9SAt.PH. 




















— Car A 






l/o 









s./.t/rrsrn 














1 






















I 














1/ 


(£r 








| 














§ /^ 










I 




•' 




5 






• 
.5 






-M-A 








1 












1 


f, 












< 


D 

5 






3 






1 


1 
























r 

n 




























u 


5 






















1 


f 


















figure 
72c 


Jt 


OS JO JS 20 .25 
• OOSS ^ ec G* ar ' i L -» — ■ "SSec- Gear- ffe/ease. 


30 .35 <Q .-4s 


t 


'~*~*-'~ Compression. 

- a?< 


»- 


Sec, 


£*~<r 


f*h Gear C 


ycle. t 





ITme — Seconds. 

Figs. 72b and 72c — Car-Movement Curves, Superimposed. Sessions K Gears. 
These Curves Drawn by Cars in Tests 



154 Draft Gear Tests of the U. S. Railroad Administration 




3- 













Test Gear No. '/2/nCbrA. 
TesT Geor No. // /n Cor 3. 
Impact Ve/oc/fv=437 MPN 




W/ Ft, 


?er sec. 

.1 
[i 
















if V s 

1 


















' 




AH ~a 


1 




x /_ 










l^J 1\j >.y **'"" 




s „'' 






7 ' 'SVi! 


Jjjj 'i ^ /j 


Ft per sec. 




















'I I l/l 

! l/l 

I ' / I I 


TfWlA 

•/ If 


i 














1 
1 


I X ! ! ' 


V 


L' 








-/.36 Ft per 


sec. 




















fTgure 
72f 


Sec ^7«7/- Compress/on 


*? ./! 




? 2 


5 


30 .35 


40 46 

























7/me— Seconds 



Dotted lines represent instantaneous car velocities as de- 
termined from the original car-movement curves. 



The irregularities are due in general to vibrations of the- 
car structure induced by draft gear action. 
Full lines represent the mean velocity curves. 



Fics. 72d, 72e and 72f— Velocity Curves, Sessions K Gears 



60 
40 
20 

20 
40 



Draft Gear Tests of the U. S. Railroad Administration 155 

FtLbs. 




Sdiicf Buffer in Car A 

Test Gear No. // ih Car 8 

iirpacf Vehctj-y=3. 6/ MPH. 



-34.247 FtLbs 



-6J96 Ft. Lbs. 



^30735 Ft Lbs. 
Work Absorbed 



figure 
72g 



-~O.0G4 



Sec. Sear Co/r, 



0JS5 Sec Gear Re/east 
?0$& Sec. Praft Gear Cyc/e— 



25 



30 



35 



40 



45 



Test Gear No. /2 /h Car A 

Test Gear No. // /n CarQ 

Anpact Velocity - — /JO M.RH. 




Test Gear No. /2 in Car A 

Test Gear No. // in CarB 

jhpacf Vetocfty — 437 M.RH. 



Time — Seconds 



Full lines represent the instantaneous kinetic energy of the 
moving cars. 

Figs. 72g and 72j — Energy Curves, Sessions K Gears 



Dotted lines represent the energy stored and absorbed 
luring the draft gear cycle. 



156 



Draft Gear Tests of the U. S. Railroad Administration 



700 












So/to* Buffer fn Cor A n 
Test Gear No. // /nCor 8. t 
/mpoct Ve/oc/ty=3.d/ MP//. 




600 




















500 
400 


























































WO 








































figure 
7ek 


*" 


.05 


JC 


7 ./£ 


.20 25 .30 35 40 4S 


1 


Sec. "Gear Cor 
— 0.2/8 


repress. 
(Sec. Draff 


Gear Cyc/i 







300 



20C\ 



Test GeorNo. /2 /r? Cor A. 
Test GeorNo.// /ru 



'est GeorNo./ 
I mpoct Ve/oc/, 



?/i. 



too 



-0.075- 



^05 



JO ./5 .20 
0./28 Sec. Gear Re/ease ■ 



25 



30 



35 



40 



45 



Sec. Gear Compress. 

— ■ 0.203 Sec Draft Sea, 



Cyc/e- 



100 












Test Gedr No. /2 /n Car A. 
Test GeorNo.// /r? Cor B. 
/mpoct Ve/oaty=437 MP//. 




600 
500 
400 
























































200 

/oo 
























































figure 
7em 





Sec. Gear Compress/on 


/0 .£ 


5 20 25 


.30 35 40 45 






-0.282 Sec 


Draff Gee 


tr Cyc/e 







Figs. 72k and 72m— Time-Force Curves, Sessions K Gears 



Draft Gear Tests of the U. S. Railroad Administration 



157 




So/id Buffer in Car /I 

Jesf Sear No. // in Car B 

/mpac-r Ve/ocrry=3.6/MfiN. 



45 



% 










Tesr Sear No./2 in Car A 

les-r Sear No. // in CarB 

/mpac-r Veioci-fv = /./M. P.H. 






1- 




































j 








1 




















figure 

7ep 




^ 














% 


.OS 

.n rrr- Sec Gear > 


JO IS 2i 
/,,» 5ec. Gear fie/ease. 


.25 JO 35 

* 


.40 .45 


k 


" ° 7 ° Compression "«*'*•« 
■ O "'tfj < ^ ec Drtrfi- Gear Cyc/e 





7 
6 










Test- Sear No./2 in Car A 

Test- Sear No. ii in CarB 

/mpac-r \/e/oafv=<4.31MPH. 




























D 














<i 


^f 




3 

2 




//' C 


















A 
















// r^ B 


-~T A ^v: 


B^^^ 














yr 






^% 


^"Ok, 






figure 
72q 




os ./ 

'OOOS Sec Sear ' 


./S 20 .25 
„ . ,»-, Sec. Gear- Re/ease. 


30 .35 40 .45 




Compression. ' 


- n -> Sec. DrarT+ Gear Cyc/e. 





77me — Seconds 



Curve D, determined from superimposed car-movement 
curves, represents combined draft gear movement and yield 
of car bodies. 

Curve C, obtained by eliminating car body yield from 
curve D, represents true combined movement of both gears. 

Figs. 72n, 72p and 72q — Time-Closure Curves, Sessions K Gears 



Curve B, traced on small drum, represents movement of 
gear in Car B. 

Curve A, derived from curves C and B, represents simul- 
taneous movement of gear in Car A. 



158 



Draft Gear Tests of the U. S. Railroad Administration 



700 






-110 s — 












Sofia/ Buff er /r? Cor A. 








600 


Test Gear No // //? Cj?r3. 










impact, l/e/ocJty-33/ Mm 








SOO 
































400 
























325,000' ^ 


> ' 






300 








J 
















y 








200 














































figure 
















72r 


6 




/ 




2 




c 





6 ear C/osure — /nches 



500\ 



X 

K400 



300 



200 



/OO 



W. 



%sf~Gear Na72 //7 Car A. 
—Test-Gear-/Vo.-//-/r7-Car-3, 



I 

impact Ve/oc}fy=4.57AfP/i. 




Gear C/osure —Inches 

Figs. 72r and 72t — Force-Closure Diagrams 
Sessions K Gears 



Draft Gear Tests of the U. S. Railroad Administration 



159 




Softd Buffer in Carsl 
7est Gear No. 23 in Car 3 



17me — Seconds 



Fig. 73a— Car-Movement Curves, Superimposed. Miner A-18-S Gears 
These Curves Drawn by Cars in Test 



11 



160 



Draft Gear Tests of the U. S. Railroad Administration 




17me - — Seconds 

Figs. 73b and 73c— Car-Movement Curves, Superimposed. Miner A-18-S Gears 
These Curves Drawn by Cars in Test 



Draft Gear Tests of the U. S. Railroad Administration 



161 




■ IS .20 

Sec Gear Compression^ 0.207 Sec. Gear Release - 

: 0.09B ' —0305 Sec. Draft Gear Cycle— 



T/me^Seconds 



Dotted lines represent instantaneous car velocities as de- 
termined from the original car-movement curves. 



The irregularities are due in general to vibrations of the 
car structure induced by draft gear action. 
Full lines represent the mean velocity curves. 



Figs. 73d, 73e and 73f— Velocity Curves, Miner A-18-S Gears 



162 Draft Gear Tests of the U. S. Railroad Administration 



80 


^■62.773 Ft Lbs. 








So//a/ Suffer- /n Car A 

7es-r Gear No23/n CarS 

/mpac-r Ve/oa'fy= 3. S1HPH. 


W 




Car A 
















40 












~-3/.d70 


FtLbs. 








W 


CarB-^ 




g~V££92 


» FtLbs eac 


h car 






FtLbs. 



















"\ 






















20 


i 


\ 










mm J2ff222 Ft Lbs. 
Work Absorbed 






figure 
73g 




^3/£3S 


FtTbs.-tYorA Done 




40 


.0 
062Sec.6earC 
0.2 


5 
ynp 

V7 


JO /S 20+ 

— O./SS Sec Gear Re/ease — 

Sec Draft Gear Cyc/e — 


2S 30 35 40 4S 



lesi- Gear No. 24 in Car A 

Tes-r Gear No. 23 /n CarS 

///pact Ve/oci+Y — /OS M.P/i. 



Test Gear Ma 24//? CarA 

Test- Gear No. 23 in CarS 

/mpact Ve/oc/ty — 4.4G M.PH 




7/me — Seconds 

Full lines represent the instantaneous kinetic energy of the Dotted lines represent the energy stored and absorbed 

moving cars. during the draft gear cycle. 

Figs. 73c and 73j — Energy Curves, Miner A-18-S Gears 



Draft Gear Tests of the U. S. Railroad Administration 



163 









! 


















Kit 














Sofia* Buffer /n Car A 
Test Gear No. 23 m Car B. 
(maact Ve/oc/tv=3.S7 M.PH. 




WO 






















300 






















400 






















300 






















200 






















AXf 






















figure 
73k 





0062 — 


JO JS .20 


.25 30 35 40 45 




Sec Gear Comi 
— 0.2H 


?/TSSS. 

7 Sec. Pr 


^Sec. Gear 
zrfrGear C 


Re/ease 

yc/e — 





300 












Test Gear No. *24 //? Car A 
Test Gear No. 23 in Cor 3. 
Impact Ve/oc/tv=/.Q5 MPtf. 




ZOO 




















zoo 

3„ 






















vl<> 


05 JO /£ 


20 25 30 35 40 45 


* 


Sec. Gear C 
t 0./73 v 


o/rfpress. Se 
Sec Draft Gi 


c. Gear Re/ease 
x>r Cyc/e — 





9 
















' 




^WO 













Test Gear No 24 /n Car A. 
Test Gear No. 23 /n Car 3. 
Impact Ve/oc/tv=4.46 MP/t. 




§600 

r 






























































J 


1 














200 






I 














100 






V 












Figure 
73m 











.05 / 

5ec Ge S^3h :ompress ' 


L 

1 

-^0305 Se 


5 2 

0.207 Sec. 
c. Draft Ge 


.25 3C 

Gear /re/ease 

or Cyc/e m 


> 3i 


S 4( 


7 .45 



Fig. 73k and 73m— Time-Force Curves, Miner A-18-S Gears 



164 Draft Gear Tests of the U. S. Railroad Administration 



s 










So/td Buffer in Car A 

Tesf Gear Nb.23in CarB 

ffrpac-f Vehcif\s-3.S7HPH. 




4 






o 
















3 


*s 


£ 


___^!^sw« 




















B 




ei 






















/ 






















figure 
73n 




■OS 


./O J5 .20 
„ ,,-r- Sec Gear- Re/ease. 


.25 .30 .35 .40 .45 




•° CC ComprVs S ,on. ' WAJO „ M _ _ . 

^ -y-, Sec. Draft Gear- Cycle. r 






17me — Seconds 



Curve D, determined from superimposed car-movement 
curves, represents combined draft gear movement and yield 
of car bodies. 

Curve C, obtained by eliminating car body yield from 
Curve D, represents true combined movement of both gears. 



Curve B, traced on small drum, represents movement of 
gear in Car B. 

Curve A, derived from curves C and B, represents simul- 
taneous movement of gear in Car A. 



Figs. 73n, 73p and 73q — Time-Closure Curves, Miner A-18-S Gears 



Draft Gear Tests of the U. S. Railroad Administration 165 







\-2.S4*-~ 










300 




Sof/of ka/Ter 


fn Car 


A 










Test Gear No. 23 //? (fir 3. 






800 




/mpact te/ociity=3.57 Af.P/z 






















700 
































600 
































500 


























































300.000%^ 






300 
































(q 200 

3 










/ 












s 


J 





















figure 


& 














73r 



/ 2 

Gear C/osure — //?c/?es 



/oo 


































Test G 


ear No. 24 n' Car A. 






600 




lest Gear No.^ 23 //? (fir B. 










Impact Vebc/fy=4.4 


6 Mm 






SOO 
























Geons 


C/osecf 






400 








390,1 


WO* 


















s 
















1* 




200 












h 












y, 


l k 








Test Gear No. 25^, 
Cor 2?--. — -"^ 




f 












■ * 


j 


figure 
73t 



















0/23 

Gear C/osure —/nc/ies 

Figs. 73r and 73t— Force-Closure Diagrams 
Miner A-18-S Gears 



166 Draft Gear Tests of the U. S. Railroad Administration 



to 




So//d Buffer /n Car A 
Tesf Gear A/a 7 in CarB 



TFme — Seco/7a J s 



Fig. 74a— Car-Movement Curves, Superimposed. Westinghouse NA-1 Gears. 
These Curves Drawn by Cars in Test 



Draft Gear Tests of the U. S. Railroad Administration 



167 



Test- Gear A/a 6 in Car A 
lesi- Gear No. 7 /n Car 3 



| 1 i 

A/om/na/ /mpocf- Ve/oc/fy /M.PH. 

It** 




Ume Seconds 

Figs. 74b and 74c— Car-Movement Curves, Superimposed. Westinghouse NA-1 Gears 
These Curves Drawn by Cars in Test 



168 Draft Gear Tests of the U. S. Railroad Administration 



6 












So/id duffer /r? Cor A. 
Test Gear No. 7/nCor BY 
/mpocf Ve/odtv=3.0$ MPH 


5 


<S r r 4.48Ft 


per sec 
















4 




*ST~ Car ~ A 




r\ 1 


^K J*J> KT— 


3.07 Ft per sec. 






3 




!\ 


— — 2.23 Ft per sec. 














2 




A 












/7.24 Ft per sec. 














/ 






3 
















figure 
744 





.05 


JO 75 .20 25 


3V 35 40 *£> 




Sec. Gear Compress 


270 Sec. Draft 






















Time — Seconds 



Dotted lines represent instantaneous car velocities as de- 
termined from the original car-movement curves. 



The irregularities are due in general to vibrations of the 
car structure induced by draft gear action. 
Full lines represent the mean velocity curves. 



Figs. 74d, 74e and 74f — Velocity Curves, Westinghouse NA-1 Gears 



Draft Gear Tests of the U. S. Railroad Administration 



169 



60 


4S935Fti 


Lbs. 








Solid Buffer* in Car A 

Test Gear No. 7 in CarB 

Imjoacr Vehdtv*~3.06MPH 


<iO 














^21539 Ft Lbs. 






20 








//,362 FrLbs 








+3,475F+Lbs. 









,U -< 


\ 




















20 




N % 


Wc 


2// Ft Lbs. 
\rk Done. 








^2Q924FtLbs 
Hbr* Absorbed 

1 




figure 
7*9 




.a 


5" 
or 


jo js -2o es 

mi,* Sec. Gear Pe/ease. 


.30 .35 40 .4S 




wo ' Compression. , 


1269 


Sec. DrcrFr 


Gear- Cyc/e. 







lest Gear No. 6 in Car A 

Test Gear No. 7 in CarB 

frpoct Velocity — O.S6 M.RH 



too, 

80 
GO 
40 


^85,/OC- Ft 


u Lbs. 








Test- Gear No. 6 in Car* 

7est Gear No. 7 in CarB 

impact VehcJ'hs=<4.l6 M.RH. 




























^CarA 


























2V,900FtL 


OS. 










^3a.400ftik 


' 






Car-ff^^ 


















pfOFtLbs 





20 
<*0 
60 
















pS 


























x \ 


























^~ 


4330 
Work- 


Ft Lbs. 
Oone. 








Wb 


3 
rk 


%380FtLbs. 
Absorbed 




OS ./o 

rift Sec. Gear Compress/on. 


's 20 .35 .30 .35 .40 
,-,,,„_, Sec. Gear Re/ease. 


4 
figure 


b 




■" 04// ® p<r OroFr Gear- Cyc/e. 


74/ 



TFme Seconds 



Full lines represent the instantaneous kinetic energy of 
the moving cars. 



Dotted lines represent the energy stored and absorbed 
during the draft gear cycle. 



Figs. 74c and 74j — Energy Curves, Westinghouse NA-1 Gears 



170 



Draft Gear Tests of the U. S. Railroad Administration 



600 














So //d Buffer fr? Cor A. 
Test Gear No. 7 fr? Car B. 
/mpoct Ve/ocftv=3.06 MPrt 




£00 






















400 






















300 






















200 






















/OO 














1 






figure 
74k 


C 


1 .05 


JL 


1 ./5 .20 .25 


.30 .35 40 45 


See Gear Compress. 



















I 



! 



lest Gear No. 8 //7 Cor A. 
lest Gear No. 7 /n Cor 3. 
fmpoct Ve/ocfti/=0.38 MPH 



.05 ./O 

—-0./43 Sec. Gear Compress/on 



./£ 



.20 .25 .30 

0.233 Sec. Gear Re/ease- 



35 



40 



45 



038/ Sec. Draft Gear C/c/e 




Test Geor No. 8 fn Cor A. 
Test Geor No. 7 fn Cor 3. 
Impact Ve/oc/ty=4/6 M.ffl. 



05 JO 

~0/24 Sec. Gear Compress/on 



.20 .25 30 
0.287 Sec. Geor Re /ease 



— ■ 0.4// Sec. Draff Gear Cyc/e 

7/me —Seconds 
Figs. 74k and 74m — Time-Force Curves, Westinghouse NA-1 Gears 



Draft Gear Tests of the U. S. Railroad Administration 171 




So/td Buffer tn CarA 

Test Gear No. 7 //? Car 3 

/m pact Ve/oc/ty = 3. OGHPH. 



-0.269 



lest Gear No. S tn CarA 

Test Gear No. 7 /n Car/3 

impact Ve/ocffy = 0.38 M.RH. 



% 



OS 



JO 



J5 



.20 



.as 



.<30 



.<3S 



.40 



45 




7est Gear No. 8 /n CarA 

lest Gear No. 7 /h CarB 

/ mpact Ve/ocrty=4./6 M.RH. 



TTme Seconds 



Curve D, determined from superimposed car-movement 
curves, represents combined draft-gear movement and yield 
of car bodies. 

Curve C, obtained by eliminating car-body yield from 
curve D, represents true combined movement of both gears. 



Curve B, traced on small drum, represents movement of 

gear in Car B. 

Curve A, derived from curves C and B, represents simul- 
taneous movement of gear in Car A. 



Figs. 74n and 74q— Time-Closure Curves, Westinghouse NA-1 Gears 



172 Draft Gear Tests of the U. S. Railroad Administration 



600 


- 




2.36" 












So//cf Buffer /n Cor A. 






soo 




lest Gear No 7 in Qfr 3. 










/mpacf l/e/oc 


ity=3. 


06A/M 






400 
















^300 
^ 200 






































227.000* 


















o too 




























figure 


% 














74r 



Gear C/osure —/penes 




/ 2 

Gear C/osure — /nches 
Figs. 74r and 74t — Force-Closure Diagrams, Westinghouse NA-1 Gears 



Draft Gear Tests of the U. S. Railroad Administration 



173 




.05 

f tf j5 ^ ychJ Compression 

°/h 



So/tcf Buffer /n Car A 
Test Gear No.32/n Car 3 



. q-?Sj1 §bo. Orcrfj- Gear Cyc/e. 

77me — Seconds 



.45 



Fig. 75a- 



-Car-Movement Curves, Superimposed. National M-l Gears 
These Curves Drawn by Cars in Test 



174 



Draft Gear Tests of the U. S. Railroad Administration 



6 






i 






Test Gear No. 33 /n Car A 
Test Gear No.32 /n Car 3 








$ 

i 






Nomina/ 


/mpoci- Ve/oc/ty /Af.Pr/. 








? 




















It 






CarB 


Car* 
0.24HPH. 








Car* 












1 










*^ 


^^ 




\ 
J 


-1 








1; 










■^t% 








<3 

5 




figure 
7S6 








* ? 


* 


& 




/O ' S5 .20 

n ,-,„ See. Gear* f?e/ease. 


.25 


•30 .35 .40 .45 


v.isjc Compression. 

- -o. 


ze 


'6 Sec Drar 


ff- Gear- Gya/e. 







/4 




Test Gear No.33 in Car -A 
Test Gear No.32 7/7 Car S 



17me — Seconds. 



Figs. 75b and 75c— Car-Movement Curves, Superimposed. National M-l Gears 
These Curves Drawn by Cars in Test 



Draft Gear Tests of the U. S. Railroad Administration 



175 




So/id Buffer //?Cor A. 
Test Geor No. 32 /r? Cor, 
/mpoct Ve/oc/ty=3.0$ MP/ 



OS 

Sec Gear Compress. 
- —0.083—!- — - 



./5 .20 

0/7/ -Sec. Gear Re/ease 
0.2S4 Sec Draff Gear Cyc/e — 




Test Gear No. 33 /r? Cor A. 
Test Geor No 32 //? Cor 3. 
fmpoct Ve/octy=/.06 M.PN 



-0.76 Ffper Sec 



f.00 Ff per sec. 

I \ 

-Q.3Sr~f per -sgg 



/ygure 
7Se 



.OS 

Sec. Gear Compress. 
0.092 — ^ ■ 



JO ./S .20 

0.174 Sec. Gear Re/ease- 



25 



.30 



.35 



40 



45 



i 



-0.2G6 Sec. Draff Geor Cyc/e- 




'st Geor No. 33 /n Cor A. 
f Geor No. 32 //? Cor 3. 
/mpact Ve/oc/tv=426 M.PK 



.05 ./0 
Sec. Gear Compress/an 
Q/04 — ■ 



0335 Sec Draff Gear Cyc/e 



7/me^Seconcts 

Dotted lines represent instantaneous car velocities as de- The irregularities are due in general to vibrations of the 

termined from the original car-movement curves. car structure induced by draft-gear action. 

Full lines represent the mean velocity curves. 

Figs. 75d, 75e and 75f — Velocity Curves, National M-l Gears 



12 



176 Draft Gear Tests of the U. S. Railroad Administration 



so 


4$638FtL 


Jbs. 








So/id Buffer in Car A 

Test Gear No.32/n CarB 

/mpact \/e/ocit\r-3.0dM&H 


40 




\ 








^2J69€rtLbs. 






so 


Cor/3^ _ 


Pi 




J(500Ft.L6s 






^3736 FrLM 



















NS ^^. 
























""^w< 


^23636 Ft. Lbs. 
Hbrk Done. 

I 




■ ■ - ' " b ^2^/66 Ft Lbs. 

Work /fbsorbec/ 

I 




figure 
7Sg 


4o 


.05 


JO J5 .20 .25 -30 .35 .40 .45 
~ ,-,. Sec. Gear- Re/ease. 




-wAA/ Qcnpression 


Oi. 


>&<?- 


Sec Draft Gear Cyc/e. 





Test- Gear A/o. 33 /n Car A 

Test Gear /Vo. 32 in CarB 

/mpact Ve/oc/fy — -106 M.RH 



ItO 



.05 



JO 



./5 



.20 



.30 



^35 



.45 



aO 

60 


8959Q7, 


rfLbs. 








Test Gear No. 33 /h CarA 

Test- Gear No. 32 /n CarB 

//npacf Ve/ocftv—4.26 M.RH. 




CdrA-^^s 




































ZtrrssrtLb, 


9. 




2D 






\^22,6G4.t 


IFtLbs. 
















Cor 8^ 
















zosrt-Lbs. 








20 












\ 


s. 






















N 




















60 




> 


^ 

44,22/JFt 
Work Done 


Lbs 








^40.3/22 rtLbs. 
Work Absorbea! 

1 


figure 
7S/ 




.05 JC 
^n/C" 1 Sec. Gear 


» J5 .20 .25 30 
,->->->/ Sec Gear- Re/ease. 


.35 40 .4, 


5 




^"■"' Compression. 



335 ^ L 


Iro-rr Gear 


Cycle. 





TTme —Seconds 



Full lines represent the instantaneous kinetic energy of 
the moving cars. 



Dotted lines represent the energy stored and absorbed 
during the draft-gear cycle. 



Figs. 75g and 75j — Energy Curves, National M-l Gears 



Draft Gear Tests of the U. S. Railroad Administration 



177 




Solid duffer in Car A. 
Test Gear No. 32 in Car 3. 
impact Velocity =3.08 M.PH 



45 



-0.254 Sec. Draff Gear Cyc/e 



O 

fy)0t 



lest Gear No. 33 in Cor A. 
Test Gear No. 32 in Car B. 
Impact Velocity =1.06 MPti. 



I 



-0.092- 



05 



JO 



J5 .20 

0/74 Sec. Gear Re/ease - 



30 



35 



■40 



Sec Gear Compress. 

0.266 Sec. Draff Gear Cyc/e - 



600- 



■45 




50O 



400 



300 



200 



/00 



Test Gear No. 33, in Cor A . 
Test Gear No. 32 in Car 3. • 
Impact Velocity =426 6d£tL 



Time -Seconals 
Figs. 75k and 75m — Time-Force Curves, National M-l Gears 



178 Draft Gear Tests of the U. S. Railroad Administration 



s 












So//d Buffer ai Car A 

7esf Gear No. 32//? CcrrB 

/mpacr Ve/oc/i-v=3.Q8M. RH. 


4 




D 





















c^£ 


T* 


22Sb^^ 




































/ 




















figure 
7Sn 




.05 


jo /5 .20 2, 

- .-.. Gee. Gear- Re/ease. 


5 30 35 40 <5 




' xA - Kl Compression 

— 


025 


j Sec Ora-ff Gear Cyc/e. , 







Test- Sear No. 33 fn Car A 

Jes-f Gear No. 32 /n CarB 

/mpacf Ve/oc/ty=*/.06 M.PH 



.05 



/S 



20 



25 



30 



35 



4V 



45 




Curve D, determined from superimposed car-movement 
curves, represents combined draft-gear movement and yield 
of car bodies. 

Curve C, obtained by eliminating car-body yield from 
curve D, represents true combined movement of both gears. 



77me — Seconds 

Curve B, traced on small drum, represents movement of 
gear in Car B. 



Curve A, derived from curves C and B, represents simul- 
taneous movement of gear in Car A. 



Fics. 75n and 75q— Time-Closure Curves, National M-l Gears 



Draft Gear Tests of the U. S. Railroad Administration 179 



4UU 






• __., 


























\So//cf puffer |//7 Car A. 


3/aooo* 




300 




Test Sear No. 32 /n £ar 3. 










Impact Ve/oafy=30$MPH 






100 










y 
















^ 




















Figure 
















7Sr 




700\ 



Gear C/o&ure — /nch&s 



600 



<0 soo 

I 

^ 400 
^300 



-2.6/ A 



Test Sear No. 33 //? Car A. 
lest Sear No. 32 //? CarB. 

1 H 



/ mpact l/e/oc/t/=426 MP/i. 




2 

Gear C/osure—/nct?es 
Figs. 75r and 75t— Force-Closure Diagrams, National Ml Gears 



180 Draft Gear Tests of the U. S. Railroad Administration 




77/ne — Seconds 

Fig. 76a — Car-Movement Curves, Superimposed. Sessions Jumbo Gears. 
These Curves Drawn by Cars in Test 



Draft Gear Tests of the U. S. Railroad Administration 



181 




TTme — Seconds 



Figs. 76b and 76c — Car-Movement Curves, Superimposed. Sessions Jumbo Gears 
These Curves Drawn by Cars 1 in Test 



182 Draft Gear Tests of the U. S. Railroad Administration 




77/77e—Seconc/s 



Dotted lines represent instantaneous car velocities as de- 
termined from the original car-movement curves. 



The irregularities are due in general to vibrations of the 
car structure induced by draft-gear action. 
Full lines represent the mean velocity curves. 



Figs. 76d, 76e and 76f— Velocity Curves, Sessions Jumbo Gears 



Draft Gear Tests of the U. S. Railroad Administration 



183 




Soiid Buffer in Car A 

Tesf Gear No.i4 in CarB 

impact VeiocJty= 326 M&H 



80 
60 


9Q740FtL 


bs. 








Test Gear No. /S in Car A 

lest Gear Afo. /4 in CarB 

irrpacf Vefocitv — 430 M.RH. 


CarrV^ 














' 






























20 








^^S 


.300 Ft Lbs. 












CarB^ 
















*~5,030Ft L 


bs. 









\ 


V 






















\ 














K 


figure 
76/ 


40 






•^ 


Work 


?FtLbs. 
Done. 








35,660 Ft Lbs. 
Work Absorbed 

1 




.05 ./O 
Tj0/ -y Sbc Goar Compression 


J5 .20 .35 .30 .3 
m /lo o^» Sec Gear Re/ease. 


5 40 45 






D347^ 


Sec. Draff- 


Gear Cyc/t. 




- —J 





Itme — Seconds 



Full lines represent the instantaneous kinetic energy of 
the moving cars. 



Dotted lines represent the energy stored and absorbed 
during the draft-gear cycle. 



Figs. 76g and 76j — Energy Curves, Sessions Jumbo Gears 



184 



Draft Gear Tests of the U. S. Railroad Administration 



600 



500 



400 



3C0 




200 



300r 



* 



200- 



7est Gear No. /S /n Car A. 
Test Gear No. /4 /r? Car 3. 
impact Ve/oc/tv±/.Q5 MPfi. 



iog- 



.05 
-0.097- 

Cor, 



JO 



Sec Gear Compress/on 



.15 .20 

-0./93 -Sec. Gear Pe/sase- 



.25 



30 



35 



40 



0290 Sec. Draff Gear Cyc/e- 



'700 



45 




£ 



Test Gear No. /S /n Cor A. 
Test Gear No. /4 /n Car 3 
fmpact Ve/oc/ty=430 MPti. 



T/me —Seconals 
Figs. 76k and 76m— Time-Force Curves, Sessions Jumbo Gears 



Draft Gear Tests of the U. S. Railroad Administration 185 



SoM Buffer in Car A 

Test Gear No. 14 in Car 3. 

impact Veiocity3.24HPH 




.45 



0246 



4 












lest Gear A/a i.5 in Car A 

lest Gear A/a/4 in CarB 

/mpact Ve/ocitv=i.OS HPH. 


2 
/ 






















































figure 

86p 


















.05 ./< 
.nno7 Sec - Gear 


? JS .20 .25 
. r>/o3 Stc- Gean Re lease. 


.30 .35 40 .45 




-0.097 c<Mrp/ ~ ess/on . "1 

o.a 


qq Sec Di~a 


■ft- Gear C 


-yc/e. 


»> 















lest Gear MxiS/n Car A 

lest Gear No./4 in CarB 

impact Ve/ocitv^AZOMPH. 






°y 












, 






J 
rt 


^h' 


















' 


















/ 






jU 














ZL 


>f 




-*r 


"\- 












M 


4 








""^^S^ 










r 












A N 


xS. 




figure 
76a 


.05 ./O 
m Q/-*f ^ ec Gear Compress/on. 9 


JS .20 .25 .30 .3 
_ /•» ■*->£■ Sec. Gear Re/ease 


5 .40 .45 


• 0347 Sec ~ Dra "ft~ Gear Cyc/e. 





ITme — Seconds 



Curve D, determined from superimposed car-movement 
curves, represents combined draft-gear movement and yield 
of car bodies. 

Curve C, obtained by eliminating car-body yield from 
curve D, represents true combined movement of both gears. 



Curve B, traced on small drum, represents movement of 

gear in Car B. 

Curve A, derived from curves C and B, represents simul- 
taneous movement of gear in Car A. 



Figs. 76n, 76p and 76q— Time-Closure Curves, Sessions Jumbo Gears 



186 



Draft Gear Tests of the U. S. Railroad Administration 



600 






-2AS"— 




— 










So//cf Buffer 


//? Car A. 








600 




7est Gear No. f4 triCarB. 












/mpact Ve/oc/ty =3.2(± 


->MP/i. 








400 










377,000* » 






















300 




































100 




































too 
















Figure 
















76r 







i 


f 




» 




1 J 


\ 



Gear C/osure — //ycfies 



60C 




3.00- 

283- 












1 1 

7est Gear No. 15 /n Car A. 








£00 




Test Gear No. /4 /n Ozr 3. 






> 






Impact Ve/oc/7y=4.3G 


M.PN. 








































300 






























t 




200 








GearC/osed 
U37000#-^ , 


1 










TesT bear Mo. f4 l^~2* 
Car 3 — r*-f 




too 






-->- 


~^Z~%st Gear No: /S 




figure 




^-*—~ 






Car A 


p^S-""^ 


let 


C 


) 


/ 




1 


> 




c 


\ 



(Gear C/osure —focfres 

Figs. 76r and 76t — Force-Closure Diacrams 
Sessions Jumbo Gears 



Draft Gear Tests of the U. S. Railroad Administration 187 




TFme— Seconds 



Fig. 77a — Car-Movement Curves, Superimposed. National M-4 Gears 
These Curves Drawn by Cars in Test 



188 Draft Gear Tests of the U. S. Railroad Administration 




&W 



(5 




lesr Gear No.3G/n Car A 
lesi- Gear A/o.3S /n Car B 



17me — Seconds 



Figs. 77b and 77c — Car-Movement Curves, Superimposed. National M-4 Gears 
These Curves Drawn by Cars in Test 



Draft Gear Tests of the U. S. Railroad Administration 



189 



5o//d Buffer //? Cor A. 
Tesf Gear No. 35 /r? Cor 3. 
im pact \/e/oc/ty=3S8 Mm 




as. 



JO 



./£ 



.20 



' — 0.055 -4— 0./59 Sec. Gear Re/ease 

Sec. Sear Conipress. 

■ 0.7/4 Sec Draff Gear Cyc/e 



25 



45 




0.355 Sec Draft Gear Cyc/e 



7/me —Seconds 



Dotted lines represent instantaneous car velocities as de- 
termined from the original car-movement curves. 



The irregularities are due in general to vibrations of the 
car structure induced by draft-gear action. 

Full lines represent the mean velocity curves. 



Figs. 77d, 77e and 77f — Velocity Curves, National M-4 Gears 



190 Draft Gear Tests of the U. S. Railroad Administration 




So//d Buffer in Car A 

lesir Gear No.3Sin CarB 

/mpact Velocit y 336 MPH 



JO ./5T 20 

Q--- Q Sec. G&ar /Pg/eose. 



3$904rtLbs. 
Work Absorbed 



.30 



figure 
77g 



*o 



m 



lest Gear Ato. 36 in CarA 
Test Gear No. 35 in Car 3 




Time — Seconds 



Full lines represent the instantaneous kinetic energy of 
the moving cars. 



Dotted lines represent the energy stored and absorbed 
during draft-gear cycle. 



Figs. 77g and 77j — Energy Curves, National M-4 Gears 



Draft Gear Tests of the U. S. Railroad Administration 



191 



600 




500 
400 
300 



5o//d Suffer in Car A. 



200 



/oo 



figure 
77k 



./O /5 .20 

0./S9 Sec- Gear Re/ease 

Sec. Gear Cbmjpress. 

0.214 Sec. Draft Gear C/c/e • 



.23 



30 



.35 



40 



45 



I 



300 



200 



/OO 













Test Gear No. 36 /a Cor A. 
Test Gear No. 35 in Cor B. 
Impact Ve/ocNv=/.06MPft 











































.05 
-0.035- 



./0 



./5 .20 .25 
-0/82 Sec. Gear Re/ease 



Sec Gear Compress. 

0.275 Sec. Draff Gear Cyc/e- 



30 



35 



40 



45 



i' M 












Test Gear No. 36 h Cor A. 




600 




















500 










































300 
































































figure 
77h? 







? JO 
Compression 


J5 20 25 30 3i 


J 4( 


45 


— 0.35B 


Sec Drot 


7 Gear Cy 


cJe 







T/me —Seconds 
Figs. 77k and 77m — Time-Force Curves, National M-4 Gears 



13 



192 Draft Gear Tests of the. (J. S. Railroad Administration 




i 













7es"f Gear No. 36 Ai Car A 

lesi- Gear No. 35 /n CarB 

firpocf Ve/ocitv =/.0S M.RH. 
























































.0 


5 /< 


? A 


5 a 


A 


5 .3 


.35 .40 45 













7esi- Gear No. 36 /n CarA 

7esi- Gear No. 3*5 in Car 3 

fotpaef Ve/oc/i-Y = 4./2 M.&H. 








^D^ 




















y C "*^^ 














/ 








- 














/y^\^ 








B \ _ 










r* Y 




fc *" 






V 


M- 


/ 






> 


x: 


^ 


^ 






lr_ 










\ 


V^-~— 


LX 




figure 
77q 


.05 /O 
*ni!/ Sec Gear Compression. 


J5 .20 .25 30 .3. 
m ~ ->s,* Sec. Gear- r?e/eaee. 


5" 4 


45 




0.355-^ 


Drafr Gt 


Bar Cyc/e. 







If me — Seconds 



Curve D, determined from superimposed car-movement 
curves, represents combined draft gear movement and yield 
of car bodies. 

Curve C, obtained by eliminating car body yield from 
curve D, represents true combined movement of both gears. 



small drum, represents movement of 



Curve B, traced 
gear in Car B. 

Curve A, derived from curves C and B, represents simul- 
taneous movement of gear in Car A. 



Figs. 77n and 77q— Time-Closure Curves, National M-4 Gears 



Draft Gear Tests of the U. S. Railroad Administration 193 



70C 






























So// of {Buffer /n QarA. , 






60C 


Test (Bear No. 35 /n Car @. 








/mpoct Vq/oc 


yfy=3 


Q8M.&H 






SOC 
































(A400 










362.00$ 






Nl 










1 






^00 










J 






40 200 

! 

<0 /oo 
5 










s 














































F/gure 


£ 








— ** 




77r 


1^500 


/ 2 

Sear C/osure — /nc/ies 


i 


j 2SS- 1 ! 

— 242" ! ^ 






G 


/est Gear No. 136//7 C 
lest Ge^^ Mn s^jn^y 


arA. 
or 3 








400 


Impact 


Ve/oaty=4/Z 


MP//. 




















i 




300 












1 
















i 
i 
I 




200 






>ar-/Vch4, 


l~f(s$Q 


%*Z 










CarB~* 






f*a& 


\gr* 


/OO 




-== 


Pc 


%st Geo 
Zar-A— 


rNo.36 
V { 


i 
i 

* 


figure 
lit 



' Gear C/osure— /ncties 

Figs. 77r and 77t — Force-Closure Diagrams 
National M-4 Gears 



194 



Draft Gear Tests of the U. S. Railroad Administration 



/a 


So/id Buffer /n Car A 
lest Gear No.20 in Car 3 


■ 










/o 




C/os/ny 


tyeed 














































CarB 
/.0SAt/?A 


/^^^ 


^< Car A 

^~Q83M.f?H. 














c^ 




J 














» 






^V 




1 














,0 










1 


\ 






<*> yi 


















c5 
.5 












1 






















1 ° 






1 

1 


3 














<*> 












t 






















11 
















figure 
16a 


w 

¥ 


.05 ./C 
.^ mi Sec. Gear Compress^ 




./£ 

0.23t 
On 


.20 .25 SO 
_, Sec Gear Re/ease. 


.35 .40 .45 


- O.c 


?37~ 


Sec 


Tff Gear 


Cyc/e. 






Time — Seconds 

Figs. 78a and 78b— Car-Movement Curves, Superimposed. Cardwell G-18-A Gears 
These Curves Drawn by Cars in Test 



Draft Gear Tests of the U. S. Railroad Administration 195 




"Time — Seconds 



Fig. 78c — Car-Movement Curves, Superimposed. Cardwell G-18-A Gears 
These Curves Drawn by Cars in Test 



196 Draft Gear Tests of the U. S. Railroad Administration 




.05 JO /5 20 .25 30 

■O.J44 Sec. Gear Compress. — -J— *— - — 0.358 Sec. Gear /?e/ea~se 
-0.502 Sec. Draft Gear Cyc/e- 



7?me— Seconds 



Dotted lines represent instantaneous car velocities as de- 
termined from the original car-movement curves. 



The irregularities are due in general to vibrations of the 
car structure induced by draft gear action. 
Full lines represent the mean velocity curves. 



Figs. 78d, 78e and 78f — Velocity Curves, Cardwell G-18-A Gears 



Draft Gear Tests of the U. S. Railroad Administration 



197 




So/a? BufTer /h Cor A 

TesTs Gear Ato.eo /n CarB 

Jhn pocT Vetoc/iy 2.7SMS?H. 



9.4/9 Ft Lbs 



-/6.484 Ft Lbs 
-3.36/ Ft Lbs. 



13.479 Ft Lbs 
^Wor/r Done 



Worn Absorbea 
78.472 Ft Lbs. 



figure 
78g 



.05 
-0/0/ -See Gear Comp. 



/5 
-0.236 



20 .25 

•Sec Gear Re/ease- 



30 



35 



40 



45 



0.337 Sec Draft Gear Cyc/e- 



too 












7esi~ Gear No. 2/ Jh CarA 

Tesi- Gear Ato. SO ki CarB 

Jtopact Ve/ocrtv — 385 M.&H. 




^72)930 Fi 


L Lbs 
^-Car A 














- 






































3C 


1 SOS Ft Lbs ^ 


30 
















Car 3± , 




J ^IJ850Fi 


'Lbs 




















«s 


46 Ft Lbs. — ' 


20 


""< 


\ 


















^ 


---< 


31.230 FtL 
WorA Don*. 


bs 


~ wm M M mi M M 


. ^^m 


SS.476FtLbs. 
HbrA Absorbed. -^, 




05 ./O 
» nuist Sec. Gear Compression. 


'5 .20 2* 


5- *0 .40 45 n & 

35Q Sec Goar ' G&SBB^ fa 




~U/44 r~ °* - . , c 
















' - I 







Time *- Seconds 



Full lines represent the instantaneous kinetic energy of 
the moving cars. 



Dotted lines represent the energy stored and absorbed 
during the draft gear cycle. 



Figs. 78c and 78j — Energy Curves, Cardwell G-18-A Gears 



198 Draft Gear Tests of the U. S. Railroad Administration 






600 












Soi/d Buffer //? Cor A. 
Test Gear No. 20 in Car 3. 
impact [/eiocitv=2.73MP/f. 




300 






1 














400 




















300 




















100 




















/GO 


















figure 
78k 





.05 ./C 
0/0/ Sec. Gear Compress 


» /5 2< 
~ 0.236 Sec. Gea, 


.25 30 


.35 40 .45 

























300 



200 



& /OO 



O .05 ./O 

-0.//9Sec. Gear Compress: 



./3 



.20 .25 .30 

-0.280 Sec. Gear Re/ease — 



.35 



43 



-0.399 Sec. Draff Gear Cyc/e- 



>600 

\ 












Test Gear No. 2/ in Car A. 
Test Geor No. 20 in Cor 3. 
impact l/eiocitv=3.85MPH 




700 
600 
SOO 
400 










































































300 

200 
/OO 




































figure 
76m 






















' 05 /O /. 
-0./44 Sec. Gear Compression -+• 


5 20 25 .30 .35 45 .50 
- 0.358 -Sec. Gear f?e/eose * 




» 0.502 Sec. Draft Geor Cyc/e — 


m 









Time —Seconds 
Figs. 78k and 78m — Time-Force Curves, Cardwell G-18-A Gears 



Draft Gear Tests of the U. S. Railroad Administration 



199 



6 












So/id Buffer- /n Car A 

Test Gear No. 20 tn Car 3 

/mpac-r Ve/oci-fv—273 M.RH. 


























c^r 


■ O 














2 




JT^ B 




















































Figure 
76n 




.OS A 

^nj^/Seo Gear* Comaress. 


? ./S .20 .25 .30 
/i? v Sec. Gear fte/ea&e. 


.35 .40 45 






-0.3^ 


~>-j Sec Dt-o 


■f? Gear Cyc/e- 

















Test- Gear No. 2/ in Car/1 

Test Gear No. 20 /n Car 3 

/mpacf Ve/oa+v=f.09 M.RH 


3 




















/ 




















& 


5" .k 


7 A 


S 2 


o .2 


S 3 


.35 40 .45 




TesT Gear No. 2/ /n Car A 

lesi- Gear No. 20 /h Car 3 

hpocf \Ze/ocity=3.6S M.RH 



7T/7?e — Seconds 

Curve D, determined from superimposed car-movement 
curves, represents combined draft gear movement and yield 
of car bodies. 

Curve C, obtained by eliminating car body yield from 
curve D, represents true combined movement of both gears. 



Curve B, traced on small drum, represents movement of 
gear in Car B. 

Curve A, derived from curves C and 
taneous movement of gear in Car A. 



represents sinu 



Fics. 78n and 78q— Time-Closure Curves, Cardwell G-18-A Gears 



200 



Draft Gear Tests of the U. S. Railroad Administration 



500 






































So/id Buffer /n Ca 


rA. 












Test Gear A/q. 20 //? 


CorB. 












/mpocr Ve/oc 


fty=ZJ9AtPH. 


























** ynn 












255,000** 


i 


Nj 200 












1 




\ 












^^*t 






>J /OO 


( — 




=- 














Gear C/osure —/nches 

Figs. 78r and 78t — Force-Closure Diagrams 
Cardwell G-18-A Gears 



Draft Gear Tests of the U. S. Railroad Administration 



201 




Test Gear No. /6 in Cor A 
lest Gear M>. il in Car 3 
C/osing Speed 



Ifrno — 9/ooono(9 



Fig. 79a — Car-Movement Curves, Superimposed. Cardwell G-25-A 
These Curves Drawn by Cars in Tests 



202 Draft Gear Tests of the U. S. Railroad Administration 



1^ 



Test Gear No./6/n Car A 

Test Gear A/o./7/nCarB 

A/o/nina/ Impact Vetoc/ty 1 M.PH 




0.203 



Time-Seconds 



Curve S/ctended to Comp/eje 
Draft Gear Cyc/e Beyond 
Range of Recording Device 



Test Gear No. /d tn Car A 
Test Gear A/o./T m CarB 
C/os/ng Speed 




CarB 



figure 
79c 



Time —Seconds 

Figs. 79b and 79c — Car-Movement Curves, Superimposed. Cardwell G-25-A Gears 
These Curves Drawn by Cars in Tests 



Draft Gear Tests of the U. S. Railroad Administration 203 




Test Gear No. 18 in Car A 
Test Gear No. 17 in Cor B. 
impact Velocity =032 M.PH 



I: 



i 



-1.34 Ft. per sec. 




§53 Ft. per sec 



•^-.867 Ft per sec. 



2/-.3G9 Ft per sec. 



figure 
79e 



10 .15 

Sec. Gear Release 
0.131 



0. 203 Sec Draft Gear Cycler- 



mi 5939 * 


t per Sec. 








Test Gear No. 18 in Car A. 
Test Gear No. IT in Car B. 
Impact Veloci ty-4.05 M PH 




W^%L 


± 


















'"*\ 


\ 






S\. J-w 














A 


'-Car A 




/» V "VA^ 


^■ f - "'Vy- 


■^ v " "V» ' 


»' ^3 92. 


F 


t per sec 






r\3 
i 1 

* 


St 2 ** 

^Cara^" 


Ft. per sec. 
















0V X 


i 
• 












e — 1.19 Ft}. 


76 


r aac 


s**&"^ 


fS*^ 


















figure 
73-T 


Sec Gear C 


§ 10 
fP/Tjpre&s/o'n 


IS .20 25 30 3S 


40 4-5 


■> 0.396 Sec 


: Draft Gear 


Cycle 





Dotted lines represent instantaneous car velocities as de- 
termined from the original car-movement curves. 



The irregularities are due in general to vibrations of the 
car structures induced by draft gear action. 
Full lines represent the mean velocity curves. 



Figs. 79d, 79e and 79f — Velocity Curves, Cardwell G-25-A Gears 



204 Draft Gear Tests of the U. S. Railroad Administration 



€0 


<Z*3*300 Ft Lbs. 








Solid Buffer in Car A. 
Test Gear No. 11 in Car B. 
Impact Velocity = 2.97 M.PH. 




40 




^r-Cor 


A 














20 




CarB/ 


^75 


7/3 Ft. Lbs. eat 


:h cor 






Lbs. 
















20 


""^ 






















21.874 Ft Lbs. 
Work Done 






Work Absorbed 




figure 
7<?g 


■4V 


.65 

Sees G«ar n Qgmpression 


.Id -IS tO .25 
Sees. Gear Release 


3 


■> 35 AO 45 




* — 0.256 Sec 


Draft Gear Cycle ' 





Test Gear No. 18 in Car A. 
Test Gear No. 17 in Cor B. 
Impact Velocity=0.92 M y PH. 



Car A 



y- 4.075 Ft Lbs. 



O 

I 



' ■Ul._. 

Car B 



b £ 



r~ 976 Ft Lbs, each 



■2123 Ft. Lbs. 
Work. Done 



■17/5 Ft Lbs. 

-.311 Ft. Lbs. 

-2049 Ft. Lbs. 

Work Absorbed 



figure 
79h 



-55 



45 



-m 

Sec. Gear Compress. 
-0.072- 1 



-35 



Sec Gear Re/ease 
-0./3F 



0.203 Sec. Draft Gear Cycle—* 



■5 



100 
80 
60 
40 


| 

tr-80.638 Ft Lbs. 








Test Gear No. 18 in Car A. 
Test Gear No. 17 in Car B. 
Impact Velocity =405 M.RH. 






s^-CorA 










































Ft. Lbs. each 












35.13/ Ft Lbs. 


20 


















CarB^^^ 
















7,3/7 Ft. Lbs. 














1 


20 


""**s 










































38.190 Ft. Lbs 
■>rk Absorbed 










^-40J54b Ft. Lbs. 
Work Done 










kv 




.0 

Sec Gear 

« ( 


5 .10 

Compression 


.15 20 .25 30 35 

Sec Gear Release 


40 AS 

f/gure 






$ Sec Draft Gear Cycle- 


~~ 


79/ 
















' 



Time— Seconds 



Full lines represent the instantaneous kinetic energy of 
the moving cars. 



Dotted lines represent the energy stored and absorbed 
during the draft gear cycle. 



Figs. 79g, 79h and 79j — Energy Curves, Cardwell G-25-A Gears 



Draft Gear Tests of the U. S. Railroad Administration 



205 



soc 














So/id Buffer in Car A. 
Test Gear No. 17 in Car B. 
Impact Ve/ocity-2.97 M./?/i. 




400 




/ 


















300 




/ 






















/ 


I 






















\ 


^ 












figure 
79k 




SecGegrCgmpressiof 


A 


? iS 20 2£ 


■30 35 AO 45 




* 0073 

«- 




—0.1 


*SS SecDrai 


f Gear Cycle. 




> 





lest Gear No. /8 in Car A. 
Test Gear No. /7 in Car 3. 
Impact Velocity- 0.92 M. PH. 



I 

^100 




—0/3/ Sec. Gear Be/ease- 
0.203 Sec Draft Gear Cyc/e - 



figure 
79/ 



-w 



45 



700 






♦- 






"Test Gear No. /8 in Car A. 
Test Gear No, /7 in Car B. 
frnpact Velocity »4.Q5 M.PH. 




sot 

400 
30C 










































A 




















f 


, 














100 




J 




V 




















V 














figure 
79m 




JOS JO 
Sec. Gear Compression 


JS 2( 


9 A 
0280 Sec C 


s zsb Js 


4 


45 


























<e 







Figs. 79k, 79l and 79m— Time-Force Curves, Cardwell G-25-A. Gears 



206 Draft Gear Tests of the U. S. Railroad Administration 



s 












da/id 'Buffer in Car A 
Test Gear No /7 m CorB 
Impact Ve/oc<tv-2.97MPH. 








o 
























A 










' 








T" 














































figure 
79/7 




g — ■ joS 


JO .IS SO -Z 

Sec. Gear Release 


S .30 .35 *0 .*t 




- a 07B Cegr CompreaJi 


* _ _ c Sec. Draft Gear Cvc/e 


* 





Test Gear A/a /din Car A 
Test Gear No/7 in CorB. 
/moacf Velocity -O.S2MPH. 




figure 
79p 



a 2Q3 Se, c Draft Gea r Cy c/e 



to a 












Test Gear A/a Id in Car A 
Test Gear No. 17 in Car B 
/mpacf Velocity = 405M.PH. 




























/ 


■**" 




















/ 






















/ 








X 


x 












S3f t 










— --^x 
















"^ 




A/is 
// A \ 


• / 








\^^ 


**\ 


/ 






















*•., 




figure 
79a 








"***•. ^^. 




JIB JO 


.IS J. 


^S JO js Y° / * s 




OJ/6 Gear Compression u.^ou 
- Q396 


Sec. Draft Gear Cyc/e J 



Time Seconds 

Curve D, determined from superimposed car-movement 
curves, represents combined draft gear movement and yield 
of car bodies. 

Curve C, obtained by eliminating car body yield from 
curve D, represents true combined movement of both gears. 



Curve B, traced on small drum, represents movement of 
gear in Car B. 

Curve A, derived from curves C and B, represents simul- 
taneous movement of gear in Car A. 



Figs. 79n, 79p and 79q— Time-Closure Curves, Cardwell G-25-A Gears 



Draft Gear Tests of the U. S. Railroad Administration 



207 





_ ... . T 1 , 








Sofo' Buffer in Car A. 










Test Gt 
/mpacl 


?or /Vo // 
Ve/ocity 


'in CarD 
'=237 M 


(P// 




























































pewo 














1 


1" 










/' 




L 










y 




V 












n$t. 


I 












* 79r 


£ 




i 




2 




i 




lest Gear No. 18 in Car A 
. Test Gear No. II in Car 3. _ 
Impact Velocity •0.9/ MPri. 



~A?~ 



\ 79S 

Gear No Id Car A. 
--Gear No/7 Con B. 



figure 



Gear C/osure 



Gear C/osure— /nches 



Figs. 79r, 79s and 79t— Force-Closure Diagrams, Cardwell G-25-A Gears 



14 



208 



Draft Gear Tests of the U. S. Railroad Administration 




So/id BufTer in Cor A 

Test- Gear Mo.2 //? Cor B 

C/os/ng S peed 



45 



T/me — Seconds. 

Fig. 80a— Car-Movement Curves, Superimposed. Westinghouse D-3 Gears 
These Curves Drawn by Cars in Tests 



Draft Gear Tests of the U. S. Railroad Administration 209 




lime Seconds 











leaf- Gear No. J/n Cor A 
7esV- Gear No.2 in Cor d 
C/os/na Qoeed 


Car B 
2.42MPH 






















— - ■ Car A 
/.O/ M.PH- 


















\ 






^ to 

1 
















-8 






* > 










Q^r 






«5 






* 

J' 












/ 
























1 














i 
\ 












a 

.5 








/ 

/ 




X 

1 


| 
£ 

t 










1 










/ 




<3 












< 


i 




». 








1 

V 


3 

i y 






























































figure 
80c 


to! 


. ,•>,,•> Sec C<e<7^- Compression 


./5 -a 


.2 

Sec. Gear 
y- Gear- Cyc 


S .JO 

/?e/eo3e. 


iS .40 .-f. 






^7 3ec-D"* 


le. 




$ 








^ 











Fics. 80b and 80c— Car-Movement Curves, Superimposed. Westinghouse D-3 Gears 
These Curves Drawn by Cars in Tests 



210 Draft Gear Tests of the V, S. Railroad Administration 













So//d Buffer /n Cor A 
Test Gear No. 2 in Car 3. 
Impact Ve/oaty=2.68 M.PH. 




<^3 Ftpt 


rsec 


















it-Car A 








*-2.69Ftper 


sec 
















CarSj 


K^-/.92 Ft per 


sec 


{-/.08 Ft. per -sec. 
























figure 
SOcf 


.05 
Sec. Gear Compress. 


10 i- 


5 .20 .2 

'eg Gear Be /ease '-* 


5 30 35 40 45 


* 0.084 "A 




0.25 Sec. Dro 


















0.420 Sec Draft Gear Cyc/er 




0347 Sec. Draft Gear Cyc/e~ 
T/me — Seconds 



Dotted lines represent instantaneous car velocities as 
determined from the original car-movement curves. 



The irregularities are due in general to vibrations of 
the car structure induced by draft gear action. 
Full lines represent the mean velocity curves. 



Figs. 80d, 80e and 80f — Velocity Curves, Westinghouse D-3 Gears 



Draft Gear Tests of the U. S. Railroad Administration 211 













So lid Buffer in Car A. 
lest Gear No. 2 in Car B. 
Impact Ve/oc/ty-2.68 M.Pti. 




Sg5308 Ft Lbs 
















>H< 














-8427 Ft Lbs. each car 




*r2.666 Ft Lbs. 




-Cor B 








r /6J00 Ft. ^Lbs. 
? Work Absorbed 










18.454 Ft Lbi 
Work Done 

\ 












figure 
80& 


.05 
Sec. Gear Compression 


.10 *5 .20 

Sec. Gear defease 


.2 


5 .30 35 4 


7 45 






'ec Draft Gecu 


. 























Test Gear No. 3 in Car A 
Test Gear No. 2 in Car B. 
Impact Velocity =1.13 M.FH 



■6.150 Ft Lbs. CarA- 

735B Ft Lbs, each car 



■Car B 



3.129 Ft. Lbs.-^ 



3440 Ft Lbs. 
Work Done 



2.919 Ft. Lbs. 
Work Absorbed 
102 Ft L 



t 5 



.05 iO JS 
0/73 Sec. Geor Compress/on ' 



0.247 Sec. Gear Release 



S 



0.420 Sec. Draff Gear Cycle 



45 

figure 
80h 



80 



GO 



40 



4SZ-65437 Ft Lbs. 








Test Gear No. 3 in Car A. 
Test Gear No. 2 in Car 3. 
Impact ; Ve/ocity =3. 65 MJPrt. 






^\fCar / 


\ 




























<r 30,338 Ft. Lbs. 














Cc 


irB-^^ 




^—1593' 


% Ft. Lbs. 








r-5,235 Ft.L 


bs. 








***». 


\ 






















^ 


^33.569 


Ft. Lbs. 








~29j864FtL 
Work Abso/ 


bs. 
-bed 








Work Done 










figure 
60J 


.05 .10 
Sec. Gear Compress/on 


.15 .2 


.2 
5Sec Gear 


5 30 


35 40 45 






















•Je *" 





°"~*Z 



Full lines represent the instantaneous kinetic energy of 
the moving cars. 



Dotted lines represent the energy stored and absorbed 
during the draft gear cycle. 



Figs. 80c, 80h and 80j — Energy Curves, Westinghotjse D-3 Gears 



212 Draft Gear Tests of the U. S. Railroad Administration 



500r 



400 



300- 



Safiaf 'Buffer /h Car A. 
7est Gear No. 2 /n Car 3. 
Impact Velocity =2.68 M/?H 




0.25 Sec. Draff Gear tyc/e 



400 




Test Gear No. 3/n Car A 
Test Gear No. 2 /n Car 3. 
Impact Ve/ociyy-//3 Mt?H. 



figure 
dOl 



W 



0247 Sec. Gear Fe/ease- 



Sf 



0.420 Sec. Draft Gear Cyc/e~ 



40 



45 



600 



500 



400 



300 



200 



/OO 




lest Gear No. 3 /n Cor A. 
Test Gear No. 2 In Car 3. 
/mpact /e/oc/fv-3.6SMPH 



0.347 Sec. Draft Gear Cye/e 



T7me— Seconds 
Figs. 80k, 80l and 80m — Time-Force Curves, Westinghouse D-3 Gears 



Draft Gear Tests of the U. S. Railroad Administration 



213 



4 












5p//cf Suffer //? CarA. a 
Test Geor, A/o.2 //? Cor 3. 
/mpoct Ve/oci1y=2.68 MPti 




3 




C~>0~ 


w 
















2 
/ 










































Figure 
SOr? 


t 


'secGtpJ. 


impress. 


/O /5 20 25 30 35 40 45 
- 0/66 Sec. Gear &e/ease A 



-0.25 Sec. Draft Gear Cyc/e- 




0.347 Sec Draft Gear Cyc/e- 

7/me — Seconds 



Curve D, determined from superimposed car-movement 
curves, represents combined draft gear movement and yield 
of car bodies. 

Curve C, obtained by eliminating car body yield from 
curve D, represents true combined movement of both gears. 



represents movement 



of 



Curve B, traced on small dru 
gear in Car B. 

Curve A, derived from curves C and B, represents simul 
taneous movement of gear in Car A. 



Fics. 80n, 80p and 80q— Time-Closure Curves, Westinghouse D-3 Gears 



214 Draft Gear Tests of the U. S. Railroad Administration 



40C 




So/id Buffer in Car/4 
Test Gear Na2 in CarB 
Impact l/e/ocifv=ze6MP* 








{ 








o^n" 


































46 too 

% 












-17Q000* 












Gear A/a 2 
Car- B 


t^/oo 










* 


figure 


<k 












60r 


° 6 




/ 




Jt 


» 


j 



Gear Closure — Inches. 



%soo\ 



400 



lest Gear A/a 3 in Car A 

Test Gear No. 2 in CarB 

im pact Velocity ==365 m. ph. 

zszr\ 




Gear Ciosure — inches. 



soo\ 



\*oo\ 



Test Gear Alo.Jin Car A 
Test GeorAlafin CarB 
impact Vefocity=f.l3MeH. 



isT 



t.tz- 



Gear A/o.c' 
Cor&\ 



€7,000 



figure 



80s 



'j-—Gear> A/a v? 
' Can W , 



Gear Closure — Inches. 



Figs. 80r, 80s and 80t— Force-Closure Diagrams, Westinghouse D-3 Gears 



Draft Gear Tests of the U. S. Railroad Administration 215 




0. 220 Sec Draft Gear Cyc/e — 

77 me — SeconcTs 

Fig. 81a— Car-Movement Curves, Superimposed, Gould No. 175 Gears 
These Curves Drawn by Cars in Test 



216 Draft Gear Tests of the U. S. Railroad Administration 



Test Gear No. 4Z in Car A 
7est Gear No. 4/ in Car B 



Nomina/ impac-f Ve/ocity ■ = l m.ph. 




figure 
6/6 



lime — Seconds. 







Tesi- 
lesi- 


Gear No. 42 /n Cor A 
Gear No. 41 in Car B 
















C/osing 


Speed 




Car 

266 


M.PHT^^y 






1, 




















^CarA 
0.797M.PH. 




5 ° 
1 














* 

b 










h' 








y^ 






4! 

1 


























* 
















I 














* 

a 


















I 






/ 






1 




















■> 










8 




5 






~kz 








1 


l' 


5 


















1 

f, 








^ / 




















4 


/ > 
























figure 
6/c 


4 


f OS JO 

, q/j4 Sec Gear Compression % 


.1 


S ZO .25 JO 


.JS 40 .45 








Sec Draff- Gear Cve/e. 




4, «„. 













Time — Seconds. 

Figs. 81b and 81c — Car-Movement Curves, Superimposed. Gould No. 175 Gears 
These Curves Drawn by Cars in Test 



Draft Gear Tests of the U. S. Railroad Administration 



217 




0720Ssc. Draft Gear Cyc/e 














Tesf Gear No. 42 //? Car A. 
Test Gear No. 4/ /n Car 3 
Impact ]fc/oc/ty=356km 




idftk 


i 
















^sOTrfxat 


TV 


ZarA 


























'V^'V 


^-3.8i 


9 Ft per sec 




























CorS-xf 






S *^ W ^-^ a 




-j 




*-//7 


Ft per^ec. 






















T 








figure 
6/f 


as /b 

Sec Gear Compress/on 


■15 2t 


1 2i 

Sec Gear £ 
Gear Cyc/e 


-, 30 


35 40 45 


* 0//4 * ■ 
•* 0.327 


Sec Draft 







7/me— Seconds 



Dotted lines represent instantaneous car velocities as de- 
termined from the original car-movement curves. 



The irregularities are due in general to vibrations of the 
car structure induced by draft gear action. 
Full lines represent the mean velocity curves. 



Figs. 81d, 81e and 81f — Velocity Curves, Gould No. 175 Gears 



218 



Draft Gear Tests of the U. S. Railroad Administration 




-0327 Sec. Draff Gear Cyc/e~ 

7/me- -Seconds 



Full lines represent the instantaneous kinetic energy of 
the moving cars. 



Dotted lines represent the energy stored and absorbed 
during the draft gear cycle. 



Figs. 81c, 81h and 81j — Energy Curves, Gould No. 175 Gears 



Draft Gear Tests of the U. S. Railroad Administration 



219 




Test Gear No. 42 /n Cor A. 
lest Gear No. 4/ /n Car a. 
impact Ve/odty=0.96 MPfi. 



/o 

— — 0/43 Sec Gear Compress/on - 



-0.244 Sec. Gear f?e/ease- 



0.392 Sec. Draft Gear Cyc/e- 



figure 
8/1 



45 



05 10 

Sec Gear Compress/on 
« 0.//4 




MGear No. 42 /n car, 
Gear No. 4/ /nCar 1 
... ?ct ye/oaty=3.S6 . 



0327 Sec. Draff Gear Cyc/e- 

T/me—Seconcts 



Figs. 81k, 81l and 81m— Time-Force Curves, Gould No. 175 Gears 



220 Draft Gear Tests of the U. S. Railroad Administration 



4 












So/id Buffer //? Cor A ' 
lest Gear No. 4/ in Cor B 
/mpact Ve/ocitv - 2.72 MPH 








\C 


















y B 














































figure 
6/n 


o 


OS 

Sec. Geor Compression 


.K> .IS JO 

~.*~ Sec. Gear /?e/eose. 


■ZS .30 .3S .<*o .*. 




*-0.O74 


\—Ufr 

0.22L 


■s Sec. Drvry- Gear Cyc/e. „ 






Test Gear No. 42 in Cor A 
Test Gear No. 4/ in Car B 
//rpoct Ve/ocify=.S6 MPH. 



O 302 Sec - Dnafi i~ Ge<»" Cyc/e. 



<5 













Test Gear No 42 fn Cor A 

Test Gear No. 4/ in Car B 

//npact Ve/oc/tv = 35S MPH 


























O 
















/ 




V ^ 








































... 


-\ 


\ 


\ 








^ 








V 


/B 


B 






**N 


^ 


^v\ 








//^~^ A 












^ 


K 




figure 
8/q 


■OS 10 
O f/4 Sec Gear Coi>V>ression.„ 


IS .20 ZS .30 

n ii? Sec. Gear Re/ease. 


3S -fO .4i 




O 321 Sec Drcr + Geon Cvc/e. 












71/ 


7?e — Secot 


70S. 







Curve D, determined from superimposed car-movement 
curves, represents combined draft gear movement and yield 
of car bodies. 

Curve C, obtained by eliminating car body yield from 
curve D, represents true combined movement of both gears. 



Curve B, traced on small drum, represents movement of 
gear in Car B. 

Curve A, derived from curves C and 
taneous movement of gear in Car A. 



B, represents simul- 



Figs. 81n, 81p and 81q — Time-Closure Curves, Gould No. 175 Gears 



Draft Gear Tests of the U. S. Railroad Administration 



221 



600 


Sp/tf BufYbr /n Cor A. Z3 Z 








500 


/mpocr \fe/oc/ry=272 M.P/i. 






































400 






























GOQOOO 1 * 


300 
















200 




























































figure 


<0 












6/r 


si 




/ 




7 






3 



Gear C/osure — /nches 




500 



400 



300 



§ 200 

f 

i /oo 



tsf Gear No. 42 /n Cor A. 
, s/ Gear No. 4/ in Cor Sr- 
/mpocT ife/oc/ty=0 .96 Mrfi 



figure 



8/s 



r W. ^PC4Q000# 

^ feS&g^fc W No. 4Q Car A 



/ 2 

Gear Closure — /nches Gear C/osure — /aches 

Figs. 81r, 8ls and 81t — Force-Closure Diagrams, Gould No. 175 Gears 



222 



Draft Gear Tests of the U. S. Railroad Administration 




1 1 ■ 

So/id Buffer in Cor A. 
Test Gear No.38 in Car B. 



Time— Seconds 



Fic. 82a — Car-Movement Curves, Superimposed. Murray H-25 Gears 
These Curves Drawn ry Cars in Tests 



Draft Gear Tests of the U. S. Railroad Administration 223 




Time- 5econd5 




Test Gear No. 39 in Car A 
Test Gear No.3£> in Car B 



Time-5econd5 



/ygure 
62c 



Figs. 82b and 82c— Car-Movement Curves, Superimposed. Murray H-25 Gears 
These Curves Drawn by Cars in Tests 



15 



224 Draft Gear Tests of the U. S. Railroad Administration 



/•Aoeft per set, 










Solid Buffer /h Car A. 
Test Gear No 38 //? Cor B. 
Impact Ve/ocity=2.76MPff 




-^ 


*~CarA 


















Do 






,-—£5- 


■■r-.'V.i, 


23? ft. per sec 








)""'» f*n* 






7M H-, 


vSec-fl 




<i *^^^^ 














&<? 


€carB 


















figure 
62cf 


05 

Sec. Gear Compression 


10 


.15 


20 

Gear Be/ease 


25 SO .35 AO 4i 





0743 Sec Draft Gear Cycle 










0397 Sec. Draft Gear Cycle - 



Time — Seconds 



Dotted linos r'-prcscnt instantaneous car velocities as de- The irregularities are due in general to vibrations of the 

termined from the original car-movement curves. the car structure induced by draft gear action. 

Full lines represent the mean velocity curves. 

Figs. 82d, 82e and 82f — Velocity Curves, Murray H-25 Gears 



Draft Gear Tests of the U. S. Railroad Administration 225 




7esT Gear No. 39 in Car A. 
Test Gear No. 38 in Car B. 
Impact Ve/ocity=0.93 M.PH. 



•1113 Ft Lbs each car 



">6;F~ 



■23961 FT LbS 
Work Done 
Two Gears 



QV 



874 Ft Lbs. 

Work Absorbed 
Two Gears 



/vgure 
82h 



^ Compression 



).7S7 Sec Gear ee/ease- 



-0.3S3 Sac. Draft Gear Oyc/e- 




o 397 Sec. Draft Gear Cycle - 



Time— Seconds 



Full lines represent the instantaneous kinetic energy of 
the moving cars. 



Dotted lines represent the energy stored and absorbed 
during the draft gear cycle. 



Figs. 82c, 82h and 82j — Energy Curves, Murray H-25 Gears 



226 



Draft Gear Tests of the U. S. Railroad Administration 



6C0 












Solid Buffer in Car A. 
Test Gear No. 38 in Car B. 
impact Velocity =216 M.Prt. 




400 
300 

2C0f 
100 






































































































figure 
62k 




■05 

Sec Gear Comgrtssior, 


■10 .15 .20 


25 .30 35 40 4i 






. Draff Gear Cy 
























Test Gear No. 39 in Car A. 
Test Gear No. 38 /n Car B. 
Impact Velocity =0.98 MRU. 



figure 
621 



■OS .10 

0J26 Sec. Gear Compression- 



-0.257 Sec. Gear Release 



-0.383 Sec Draft Gear Cycle- 



600 












Test Gear No. 39 in -Car A. 
Test Gear No. 38 in Car B. 
Impact Velocity = 3.4G M.PH. 




































































100 






































1 


figure 
82m 




OS ft 

■ — 0JZ7 Sec Gear Compress/c 


) 


15 .20 2 


5 .3. 

Gear &eleas 
Draft Gear C 


3S A 


45 






















"-"-" ~""' 


y^lc 







Time — 'Seconds 
Figs. 82k, 82l and 82m— Time-Force Curves, Murray H-25 Gears 



Draft Gear Tests of the U. S. Railroad Administration 227 













5o//c/ Suffer in Car /9. 
Test Gear No. 35 in Car 3. 
Impact Velocity -Z7GM.RH. 






c x~ 


h-Jf 


























































figure 
S2n 


1 .OS 


10 15 ZO 

. ,^-,sec. Gear Release 


ZS .50 35 .40 .45 


« 


Q ...jSec. Praft6ear Cycle 















Test Gear No. 39 in Car A. 
Test Gear No. 38 in carB. 
Impact Velocity =0.38 M. P. H. 


























1 


~~*di*c 


















^ 




—<? 










figure 
62p 


<" ^-^ 












.OS -10 
„,^_Sec. Gear Compression 


If -ZO 


ZS 30 3S 
Gear Release 


.40 4S 


0333 5ec " Prof? Gear Cycle 


, 






Time -Seconds 



Curve D, determined from superimposed car-movement 
curves, represents combined draft gear movement and yield 
of car bodies. 

Curve C, obtained by eliminating car body yield from 
curve D, represents true combined movement of both gears. 



Curve B, traced on small drum, represents movement of 
gear in Car B. 

Curve A, derived from curves C and B, represents simul- 
taneous movement of gear in Car A. 



Figs. 82n, 82p and 82q — Time-Closure Curves, Murray H-25 Gears 



228 



Draft Gear Tests of the U. S. Railroad Administration 





Solid Buffer m Car A 


2A4— A 






lest Gear A/o. 33 in Cor B 

1 1 ' 








/mpaci Ve/ocrfy = Z76 MPH 














































smtito* 
















r 


























%, 












figure 


* 










\. 


62r 



Gear C/osure - Inches 



^ 


















£ 




Test 6 ear No. 39 in Cor A 










Test Gear A/o. 38 in C 


ZarB 






fit 6 


Impac 


r ve/oc/r, 


v =offsn. 


rn. 
































-24S - 




















, 












just- 
ly 


i 

P ! 














*M 
































P-G& 
131 


or Closed 
7.000* 












— J «*"* 


1 

1 


figure 




f 








—- ^J 


— » ; 


&t 



l l T 

Test Gear A/a 39 in Car A 



Test Gear A/o. 38 in Car B 

k— V \— 



Impact Ve/ocity = 0.96 MPH. 



-0-63- 



,46,000' 



6eorA/o.33 
Cor A 



figure 



82s 



Gear C/osure -Inches 



Gear C/osure -Inches 



Figs. 82r, 82s and 82t — Force-Closure Diagrams, Murray H-25 Gears 



Draft Gear Tests of the U. S. Railroad Administration 



229 




So//d Buffer in Car. A 
lest Gear Na26 //? CorB 



77me — Seconds 

Kig. 83a — Car-Movement Curves, Superimposed. Christy Gears 
These Curves Drawn by Cars in Tests 



230 Draft Gear Tests of the U. S. Railroad Administration 




7esr Gear No. 21 in Car A 
Test Gear No 26 in Car B 



/Vom/no/ /mpocr Ve/oc/fy / M.PH 



so 



35 



figure 
63b 



/3 




Tesr Geor Na27/n Car A 
Test- Gear No. 26 in Car 3 



(fifc 



Compression 



- 0. 339 SsC Draft Gear C yc/e 



Time — Seconds 

Figs. 83b and 83c— Car-Movement Curves, Superimposed. 
These Curves Drawn by Cars in Tests 



Christy Gears 



Draft Gear Tests of the U. S. Railroad Administration 



231 





lest Gear No. S3 /n Cor A. 
lest Gear No 62 /n Cor B. 
Impact Ve/oc/ty=313 MPH. 



7/me — Seconds 



Dotted lines represent instantaneous car velocities a9 de- 
termined from the original car-movement curves. 



The irregularities are due in general to vibrations of the 
car structure induced by draft gear action. 
Full lines represent the mean velocity curves. 



Figs. 83d, 83e and 83f— Velocity Curves, Christy Gears 



232 



Draft Gear Tests of the U. S. Railroad Administration 




S6//d Buffer- /n Car A 

Test Gear No. 52 /n Car B 

/m pact Ve/oc/ty=3S6HPH. 



27.206 Ft Lbs 



6./04 Ft Lbs 



23/35 FY: Lbs 
Work Absorbed 



figure 
S3g 



~0.059- 



/O /£ 

-0/4/ Sec Gear Re/eose- 



Sec Gear Comp 

[— 200 Sec Draft Gear Cyc/e- 



25 



30 



35 



40 



45 



Test Gear No. 53 in Car A 

Test Gear No. 52 in Car B 

/mpact Vehcft y — 3. 73 M.F>H. 




Time — Seconds 



Full lines represent the instantaneous kinetic energy of 
the moving cars. 



Dotted lines represent the energy stored and absorbed 
during the draft gear cycle. 



Figs. 83c and 83j — Energy Curves, Christy Gears 



Draft Gear Tests of the U. S. Railroad Administration 



233 



600] 



soo 




<So//d Buffer /n Cor A. n 
Test Gear No. 52 in Cor B. 
frnpact Ve/oc/tV=3.56 M.PH 



400 



300 



200 



100 



figure 
63k 



I 



—0.059 



JO ./5 .2Q 

-0./4/ Sec. Gear Re/ease— 



Sec. Gear Compress. 

0200 Sec. Draff Gear Cyc/e- 



.25 



30 



35 



40 



^300 



45 



% 



% 200 
I 

I 



Test Geor No. S3 in Car A. 
Test Gear No. £2 //? Cor B. 
/mpoct l/e/oc//y=/ .07MFN 



.05 



./o 

-0/04- 



.15 



■^0.063- 

Sec.Qear Comp. Sec. Gear Re/ease 
0/67 Sec. Praff Gear Cyc/e- 



20 



25 



.30 



35 



40 



45 



700 



600 



50O 



400 



300 




-0.339 Sec. Draff Gear Cyc/e — 

7/me —^Seconds 
Figs. 83k and 83m — Time-Force Curves, Christy Gears 



234 



Draft Gear Tests of the U. S. Railroad Administration 




45~ 



Test- Gear Ah. 53 in Car/* 

les-f Gear A/o. 52 in CarB 

Im pact Ve/ocrty = I.O"7 M.RH 



% 



OS~ 



JO 



^6 



~^5 



~W 



~35 



-&F 



.45 




s4G 



77me — Seconds 

Curve D, determined from superimposed car-movement Curve B, traced on small drum, represents movement of 

curves, represents combined draft gear movement and yield gear in Car B. 

of car bodies. Curve A, derived from curves C and B, represents simul- 

Curve C, obtained by eliminating car body yield from taneous movement of gear in Car A. 
curve D, represents true combined movement of both gears. 

Figs. 83n and 83q — Time-Closure Curves, Christy Gears 



Draft Gear Tests of the U. S. Railroad Administration 235 



* 



400 


















i 






Sol/of Buffer /n Cor A. 








400 


Test Gear No. l SZ //? Cor B. 










Impact Ve/oc/ty=3.56M.m 








300 








2S0.00O* 


* 
























AHJ 
























/"" 










(00 














figure 
















SSr 







/ 






2 




>3 





Sear C/osc/ne — /nches 



600\ 



300 



-2.23- 

-ZQ7- 



7&st Gear No. £3 in 'Car A. 



lest Gear No. 5 2 /n Car 3 



impact Ve/od/ty=373 M.Pti 




0/23 

Gear C/osure — //?c/?e3 
Figs. 83r and 83t — Force-Closure Diagrams, Christy Gears 



236 



Draft Gear Tests of the U. S. Railroad Administration 




4S 






0.237 



77me — Seconds 



Fig. 84a — Car-Movement Curves, Superimposed. Miner A-2-S Gears 
These Curves Drawn by Cars in Test 



Draft Gear Tests of the U. S. Railroad Administration 



237 



cfjft 



t<>1 



fi* 1 



Tesi- Gear Na21in Cor A 
Test Gear Na26in Car B 



Nomina/ /mpoc-f Ve/oc/fy /MPH 




Compression ^^ Sec Dr . Qft Geon C yc/e 




17me — Seconds 



Figs. 84b and 84c — Car-Movemi vr Ci rves, Superimposed. Miner A-2-S Gears 
These Curves Drawn by Cars in Test 



238 



Draft Gear Tests of the U. S. Railroad Administration 




Test Gear No. 27 /n Car A 
lest Gear No. 26 /n Car 3. 
Impact Ve/oc/ty=/.07Mr°N 



-/.S7 Ft per sec 
■Car A 




0.98 Ft per <sec. 



^^0.98F? 
+—0.44F 



7 Ft per sec 



0.44 Ft per sec. 



figure 
84e 



IE 



*&ftE5j- 



-0/38 



TO 

Sec. Gear Pe/ease 



45 



Q2/2 Sec Draft Gear Cyc/e-~- 













lest Geo/ 
Test Gear 
Impact 1 


-No. 27 in Car A. 
■ No. 26 In Car B. 
/e/oc/ty=32/M.m 




<$470S Ft/ 


■>er sec 


















T" 


/-Cor A 




>v /V 






3/ f Ft. per 


.sac.^ 








} 




232 Ftp 


?r sec 


; •- 














^S^ 




k ***»^^ 








/.2A 


Ft oe, 














l~zT' 




"C-Sr B 














figure 
S4f 






\ Sec. Geo 


S /O 
r Compress/on 


& 20 2*5 30 35 40 
„,<,., Sec. Gear Re/ease 


45 


I '■ 0.425 Sec 


7. Draft Get 


?/- Cyc/e — 





lime — Seconals 

Dotted lines represent instantaneous car velocities as de- The irregularities are due in general to vibrations of the 

termined from the original car-movement curves. car structure induced by draft gear action. 

Full lines represent the mean velocity curves. 

Figs. 84d, 84e and 84f — Velocity Curves, Miner A-2-S Gears 



Draft Gear Tests of the U. 5. Railroad Administration 239 



60 












So//d Buffer *? Car A 

7est Gear No. 36 in CarB 

/mpoc-f Ve/octtv 2.47MPH 




^JQ/OSfrLbs 

^J 
















20 














k At '6 56 ft Lbs 








Idl 7407rtLbs. 






r2,/67rtLb&. 


O 


< ^ i -« «n»_™ 




1 - 







J 

~/3 l 287FrLbs. 












Wor/c Absorb*?. 


40 






JS295rt.Lbs 
Work Done 

1 












fvgure 
64g 


05 JO /S 20 25 
m „ or . Set? Gear' .1 n , Q -, Seo. Gear- /do/ease. 


JO 35 40 46 




0SS Corrpress/on ' Q/9 ^ 

Q "S7 S *° Draft Gear 


Cycfa. 





oS /o 

• Q/33 ^ 9C ( ^ ear Compression. 



lesf Gear No. 27 /h Car/I 
7esf Gear No. 26 /h CarB 
Jepacr Ve/oc/fY~32/ M.RH. 




Q.4C5 SifCr ° rcrfi ' Goay ~ C Y C, ° 

Wme — Seconds 



Full liru-s represent the instantaneous kinetic energy of 
the moving cars. 



Dotted lines represent the energy stored and absorbed 
during the draft gear cycle. 



Figs. 84c and 84j— Energy Curves, Miner A-2-S Gears 



16 



240 



Draft Gear Tests of the U. S. Railroad Administration 



600 



4O0 



300 



So//d Buffer //? Cor A 
TesT Gear No. 26 //? Car B. 
Impact Ve/ocitv=247MJ?N 




.05 
0.035 



Sec Gear Compress 



45 20 25 
0./S2 Sec Gear Re/ease 



0.287 Sec Draff Gear Cyc/e- 



45 



400 

3*» 



lest 6 ear No. 27 /n Car A 
Test Gear No. 26 //pGorB. 
fmpact Ve/oc/tv^Q7/^Pr/ 



<k 



200 



/00 



0.074- 



.05 



'O JS 20 

0./38 Sec Geor Re/ease— 



25 



30 



40 



Sec Gear Compress 

02C2 Sec Draft Geor Cyc/e 



45 



600 












' 


Test Sear No 27 in Car A 
Test Geor No. 26 /n Car B. 
impact Ve/oc/tv =32/ M.Pff. 




400 










































200 








































figure 
84m 


/oo 






















. 


r 











05 K 
"-0./38 Sec Gear Comf. 


7 


/5 2 

02 


.25 3 


35 40 


45 





































Time - Seconds 
Figs 84k and 84m — Time-Force Curves, Miner A-2-S Gears 



Draft Gear Tests of the U. S. Railroad Administration 241 




.4S 











lest Gear No.27 /n Car A 

Test Gear No.P6/'n CarB 

tmpocf Ve/oc/tv=/.01 M.RH. 






















































^^~ 
















rTffure 
S4p 


.OS 


./o /s 20 

-_o tr>j> Sec. Gear- &e/eose. 


-S\ 


5 .30 .35 .40 -as 


?"""" Compress/on 
- 0. 


2 ,-, S* 


c. Drcrry- ( 


?st//~ Cyc/e. „ 






Tes-f Gear No.81 in Car A 

Tesf- Gear No.26 tn CarB 

/rnpaci- Ve/ocfj-y~=3.2l M.PH. 



0-425 



"TTme — Seconds 



Curvf I), determined from superimposed car-movement 
curves, represents combined draft gear movement and yield 
of car bqdies. 

Curve C, obtained by eliminating car body yield from 
curve D, represents true combined movement of both gears. 



Curve B, traced on small drum, represents movement of 

gear in Car B. 

Curve A, derived from curves C and B, represents simul- 
taneous movement of gear in Car A. 



Fics. 84n, 84p and 84q — Time-Closure Curves, Miner A-2-S Gears 



242 



Draft Gear Tests of the U. S. Railroad Administration 



i 

I 

l 



400 
300 
200 



/OO 



600 



500 
400 
300 



20fr 



/OO 



So//of Buffer /n Car A. 



-2,50- 



Test Gea r No. 26 /n CarB. 



impact , Ye/oc/ty=247 MPtf. 



T/35,000* 



/ 2 

Gear C/asure — /nc/?e$ 



Figure 



84r 





■'-„ -2S9" 


— t 






<~'*r i i 






Test Gear No. $7 In Cor A. 


1 






Test Gear No. 26 //? Car B. ^ 


K 






fmpact Vebc/ty=32/ Af.P/i. \ 


to 












1 


: i 














JCVJ 












< 


i k 












1 


II 














■\ 










Gear C 


'/osecf . 


|J5> 








/ub.uuv**-—^; 


LGeor 


C/osed 
WO* 


[r 




T r-— 


J rigor 


eS4t 



(Gear C/osure - /rcft^s 



Figs. 84r and 84t — Force-Closure Diagrams, Miner A-2-S Gears 



Draft Gear Tests of the U. S. Railroad Administration 



243 




77me — Seconds 

Figs. 85a, 85b and 85c— Car-Movement Curves, Superimposed. Waugh Plate Gears 
These Curves Drawn by Cars in Test 



244 



Draft Gear Tests of the U. S. Railroad Administration 













5o//d Buffer /n Cor A 
Test Geor No. 49 /n Car 3. 
/mpact Ye/oc/?v=/.e4MP/i. 




s~234Ftt 


o&r sec 
















in 


^s^-QjrA 


























\L 


-—/.4/ Ft per 


sec 














CarB^ 


'^^ 






0S5_Ff 


per sec 






figure 


OS 10 is 20 

Sec Gear Compress. \—Sec. Gear Re/eose 0/35 

^^ 0.230 Sea Draff Geor Cycle - 


25 30 35 40 -4S 





T/me— Seconds 



Dotted lines represent instantaneous car velocities as de- 
determined from the original car-movement curves. 



The irregularities are due in general to vibrations of the 
car structure induced by draft gear action. 
Full lines represent the mean velocity curves. 



Figs. 85d, 85e and 85f— Velocity Curves, Waugh Plate Gears 



Draft Gear Tests of the U. S. Railroad Administration 



245 




So/id Buffer /n Can A 

lest Gear No. 49 th Car B 

/rnpacf Ve/oc/f y=/.94 M.f>H 



/2/t3drtU>e. 



^S.729 Ft Lbs. 
Work Absorbed 



figure 
85g 



.25 



30 



JS 



40 



•<*d 




7est Gear No. SO/n Cor A 

Test Gear No. 49 in Car 3 

/mpacf \Se/oafY=3.Q2 M.PH. 



05 /O 

j,,~ Sec Gear Compress/on. t \ m 



Sec Draft- Caar 



Time —Seconds 



Full lines represent the instantaneous kinetic energy of 
the moving cars. 



Dotted lines represent the energy stored and absorbed 
luring the draft gear cycle. 



Figs. 85c and 85j — Energy Curves, Wauch Plate Gears 



246 



Draft Gear Tests of the U. S. Railroad Administration 



600\ 




400 












Bsf Geor No. 50 /n Cor A. 
Test Geor No. 49 /n Car 3. 
import Ve/oc/tv=/.06 A/JW 




\goc 










































uoo 

\ 
























.05 JO JS 


.20 2 


5 .3 
1 Sec. Geo 


.35 40 


45 


1 




-0.4/9 Sec. Draft Geo> 






$ 




















-0292 Sec. Draft Geor Cyc/e- 

T/rr?e —Seconds 



Figs. 85k and 85m— Time-Force Curves, Waugh Plate Gears 



Draft Gear Tests of the U. S. Railroad Administration 



247 



s 










So//d Buffer /n Car A 

lesi~ Gear Na49/n Car B 

/mpac-f Ve/odi-v=f.34MPH 




4- 




















3 




C , 


D 




















2 




S^ 
















/ 


















figure 
6Sn 




.05 J 


J5 .20 
,-,/-,- Sec. Gear- Re/ease. 


.25 .30 .35 .40 .45 




■°°^Compre 


ss/on. 
0.23C 


Sec. Draff 


Gear- Cyc/e. 





Test Gear NaSOin Car A 

les-f Gear A/o.49/n CarB 

//n paci" Ve/oc/-fy*=/.OGMPH 




a 










Test Gear /VaSO/r? Car A 

lesr Gear No.49 /n CarB 

/mpacf Ve/ocii-v=3.02MPH 




6 

5 
4 
3 








































/ 


<z~- 


















/ 




















/ 




-^v 














2 






\ ^ 








X B 




£**«^4 




























figure 

esq 




.05 JO 
-*,,*. Sec Gear- Compression 


Jt 


F .20 .25 .30 .35. .40 .45 
-.^ Sec Gear- Re/ease. 




- 0.292 Sec 


Draft Geo, 


p- Cyc/e. 


_J 





Time — Seconds 



Curve D, determined from superimposed car-movement 
curves, represents combined draft gear movement and yield 
of car bodies. 

Curve C, obtained by eliminating car body yield from 
curve D, represents true combined movement of both gears. 



Curve B, traced on small drum, represents movement of 

gear in Car B. 

Curve A, derived from curves C and B, represents simul- 
taneous movement of gear in Car A. 



Figs. 85n, 85p and 85q — Time-Closure Curves, Wauch Plate Gears 



248 



Draft Gear Tests of the U. S. Railroad Administration 



400 




Gear C/osure —//Tcfres 
Figs. 85r and 85t — Force-Closure Diagrams, Waugh Plate Gears 



Draft Gear Tests of the U. S. Railroad Administration 



249 





Test Gear No.4T in Car A 
Test Sear Na46in CarB 



A/om/na/ 



Test Gear No.41 in Car A 
Test Gear Na46in CarB 




TTme — Seconds 



Figs., 86a, 86b and 86r: — Car-Movement Curves, Superimposed. Bradford K Gears 
These Curves Drawn by Cars in Tests 



250 Draft Gear Tests of the U. S. Railroad Administration 




0323 Sec Draft Gear Cyc/e 



T/me — Seconds 



Dotted lines represent instantaneous car velocities as 
determined from the original car-movement curves. 



The irregularities are due in general to vibrations of the 
car structure induced by draft gear action. 
Full lines represent the mean velocity curves. 



Figs. 86d, 86e and 86f— Velocity Curves, Bradford K Gears 



Draft Gear Tests of the U. S. Railroad Administration 



251 



So/a/ Buffer Art Cor/\ 

Test- Gear No.4Gth Car 8 

/m paci- Ve/ocrty e.Q4MJ?K 




Test Gear No. 47 in CarA 
lesi- Gear- No 4€ ai CorB 
/m poct Vetocfry— 210 M.RH. 




os to 

0J37 l?wc Geer ^fppression. 



eo 85 30 

- Q !36 ^ c Geo/— RetoosG. 



q J2J Ssc OrysrfV- Gear- C yc/o. 



W/ne — Seconds 



Full lines represent the instantaneous kinetic energy of 
the moving cars. 



Dotted lines represent the energy stored and absorbed 
during the draft gear cycle. 



Figs. 86c and 86j — Energy Curves, Bradford K Gears 



252 



Draft Gear Tests of the U. S. Railroad Administration 



600 












Sof/d Buffer /n Car A. 
Test Gear A/o. 46 /r? Cor 3. 
impact Ve/oc/ty=2.Q4 M.PH 




J>00 




















40U 




















300 




















ZOU 






















JOO 




















figure 
66k 





.05 
Sec. Gear Compress^ 

— °^- 0. 235 


/O J5 .20 

Q/36 Sec. Geor /rb/eose-^ 

•Sec. Draft Gear Cyc/e- — 


.25 .30 .35 40 45 




0.323 Sec. Draft Geor Cyc/e 

7/me Seconds 
Figs. 86k and 86m — Time-Force Curves, Bradford K Gears 



Draft Gear Tests of the U. S. Railroad Administration 253 



+> J 
S 



*., 



<5 













So//d Buffer in Car A 

lest Gear Na46in CarB 

//ryaaci- Ve/oc/-rv-2.04MPH 


























C^^T- 


O 
















^^ B 


^^^ 




^r 




































figure 

sen 




.05 Jt 


) JS .20 

. -,.,- Sec Gear- Re/ease. u 


.25 .30 .35 .40 .45 


" uajU Compress/on. 

r- 0.2 


-,,- Sec Dr-crff- Gear- Cyc/e M 






7T/ne — Seconals 

Curve D, determined from superimposed car-movement Curve B, traced on a small drum, represents movement of 
curves, represents combined draft gear movement and yield gear in Car B. 

of car bodies. Curve A, derived from curves C and B, represents simul- 

Curve C, obtained by eliminating car body yield from taneous movement of gear in Car A. 
curve D, represents true combined movement of both gears. 

Fig. 86n, 86p and 860 — Time-Closure Curves, Bradford K Gears 



254 



Draft Gear Tests of the U. S. Railroad Administration 



400 
300 
200 



So/fof Buffer /r? Car A. 



-2.45' 



Test Gear No. 46 '//? Car 3. 



/mpact ^ \fe/ocity=2.04 MP/i 




207000*i 



%soo 




Gear 


• C/osure — /nc/?es 










m i - 










^400 
| 


Test 6 


i — *f^ — t — 

?ctr No. 47 //? Car A. 










Test Gear/va *to /n uar o. 
Impact Ve/oc/t\/=2J5MPff. 










Q) 


















D 300 

k 

200 








Gear C 
270.00 


:/OSeaf 


» i 












^1 


x_ Gear 
f 2?OL 


SSr" 












i\ 














,i 




<ar.M?.4Z 

figure 


/oo 




7t 


?st Sear 


No. 46 


^ J 


y Car A 






oar a^>=. 






66t 



Gear C/osure —/nc/iee 
Figs. 86r and 86t — Force-Closure Diagrams, Bradford K Gears 



Draft Gear Tests of the U. S. Railroad Administration 255 



A 


So//d Buffer /n Car A 
Test Gear No.SS/n CarB 


Car B 
/.54M.PH 














1 

C/os/ng Speed 




Cor/H 

0.35MRH. 












Mr- 






1 










1' 


/ 




vj. "sir 

fvL 


V 


(0 


1 




























figure 
67a 




k 


M 


.OS 
- OD7~' ^ ec Gear m 


JO ./S .20 .2S .30 .35 40 #£ 
_ n/i>£> Sec Gear /Pe/eose. 


F 


^"""Co/7pr-esston ~~ j~Sec Draft Gear Cyc/e, 






TTme — Seconcte 

Figs. 87a, 87b and 87c — Car-Movement Curves, Superimposed, Harvey Springs 
These Curves Drawn by Cars in Tests 



1? 



256 Draft Gear Tests of the U. S. Railroad Administration 




Solid Buffer /n Car A. 
Test Gear No. 55 /n Car 3. 
Import Ve/oc/ty=l.97 M.Prf. 



2.26 Ft per sec. 



■ — 0.5/ Ft per sec 



figure 
TS7c/ 



OS 

Sec. 6eor Compress. 
- —0.077— 



./O V5 

Sec. Gear Re/ease 
0/26 



0.203 Sec. Draft Gear Cyc/e- 



25 



30 



35 



40 



45 




45 



0.296 Sec. Draff Geor Cyc/e 



7/me— Seconds 



Dotted lines represent instantaneous car velocities as 
determined from the original car-movement curves. 



The irregularities are due in general to vibrations of the 
car structure induced by draft gear action. 
Full lines represent the mean velocity curves. 



Figs. 87d, 87e and 87f — Velocity Curves, Harvey Springs 



Draft Gear Tests of the U. S. Railroad Administration 257 




Sofia/ Buffer in Car A 

Test Gear No. 55 in Car 8 

impact Velocit y —i.S7 M.RN 



-/(705 TfrLbs. 

i 
6Q/r*Lbs. 



~e.s69rf-.ibs. 

Hbrk Absorbed. 



F/gure 
87g 



25 



.30 



.35 



40 



45 



Test Gear No. 56 in Car A 

lest Gear No. 55 in Car 8 

impact- l/e/ocity = i.02 M.RH. 



/OO- 



80 



.05 JO 

, q //7 Sec. Gear- Carrpress/on. 




7est Gear No, 5€in CarA 

7est- Gear No. 55 in Car B 

impact Veiocity=a.33 MPH. 



20 ^S 

Gear &o/eose. 



4S 



- 0. 29G ^ ec Draff Gear Cyc/e 



TTme — Seconds 



Full lines represent the instantaneous kinetic energy of 
the moving cars. 



Dotted lines represent the energy stored and absorbed 
during the draft gear cycle. 



Figs. 87c and 87j — Energy Curves, Harvey Springs 



258 Draft Gear Tests of the U. S. Railroad Administration 



600[ 




T/me— ^Seconds 
Figs. 87k and 87m — Time-Force Curves, Harvey Springs 



Draft Gear Tests of the U. S. Railroad Administration 259 



6 










So/td Buffer tn Car A 

Test Gear A/o. SStn Car 3 

/mpact Ve/oc/tv—/.S7MfiH 
























J 






V P_ 


























































figure 
87n 




.OS 


./ 


J5 .20 .25 -30 .-35 ftO .-45 
f->Q Sec. Gear- Releas^ 
)2Q3§*c Qr-eff- Gear- ^ Cyc/e. 




' oo7-r Compress . oA . » 




Test Sear No.SC/n Car A 

7est Sear Mo.5S/n Car 8 

Jrnpac-f Ve/oc/f y =*/.0 2M.PH 



(5 



Test- Sear NaSStn Car A 

Test Sear No.SSin Car 3 

/mpoc-r Ve/oc/+ y=2. 33M.PH. 




45 



ITme — Seconds 



Curve D, determined from superimposed car-movement 
curves, represents combined draft gear movement and yield 
of car bodies. 

Curve C, obtained by eliminating car body yield from 
curve D, represents true combined movement of both gears. 



Curve B, traced on small drum, represents movement of 

gear in Car B. 

Curve A, derived from curves C and B, represents simul- 
taneous movement of gear in Car A. 



Figs. 87n, 87p and 87q — Time-Closure Curves, Harvey Springs 



260 Draft Gear Tests of the U. S. Railroad Administration 



400 



300 



So/taf 



Test Gear No. 55 ' /r ? Car 3. 



200 



too 



-1.76"- 



^uffer 



//? Car A 



/mpact ]/e/oc/ry=/.37 MrVf. 



243,000* 




/ 2 

Gear C/osure—//?c/?e$ 



600 



500 



400 



300 



200 



/00 



-/.76'± 



7esf (jear A/b. 56 //? Car A\. 



Test Gear No. 55 A cj?r]s. 



/mpact l/e/oc/ty=233 M$ff. 



245,000* 
Gear C/ osed 
Car B- 



Test Gedr~No. 
Car B- 



Si? 




-300,000**- . 
I ^-Gear C/oseaf 



lest Gear A/oTt56' 
Car A 



Figure 



87t 



Gear C/osure —/nc/ies 
Figs. 87r and 87t — Force-Closure Diagrams, Harvey Springs 



Draft Gear Tests of the U. S. Railroad Administration 261 



6 
5 

4 


























\ 






















t 






1 3-t 


CarB 
Q98HPH 




3 










<?Mu~ 






\^\ 


\ s 








$ 






r 










1 










1 \ 


1 

^ 




r 










^ 








? 


figure 
88a 


%$ 


05 ./o vs 

„ ,„ > Sec Gear Compress/on 


1 * 




or, 

L 


.25 30 35 40 t4i> 
T „ Sec. Gear- Re /ease. 


**• Q/64 ^ 




\-crrr Gear- Cyc/e. 





















/<? 






1 1 1 

lesr Gear A/o.S9/n Car A 
7esT Gear No.58 /n Car B 








1 

o /o 








C/oi 






















































- p 


















1 










CarB 
/.7/M2H- 






















ff 


* — 


















S'S 






1? 






4 
3 








1 

1 


* 
* 


















•/ 


















1 








1 






P / 












°3 >*" 


t 






t 
< 
i 


3 
5 




\ 










S3 

9 


* 










/T&t/re 
86c 


/ 


.Off /<? /ff 

. ,-,rr Sec Gear Compression 


.20 .25 .SO .35 
_ i ni Sec. Gear- Re/ease 




.-#? .45 








■356 


Sec Draft- Gear Cycle 





TTme — Seconds 

Figs. 88b and 88c — Car-Movement Curves, Superimposed. A. R. A. Class G Springs 
These Curves Drawn by Cars in Tests 



262 Draft Gear Tests of the U. S. Railroad Administration 



Test Gear No. 59 /n Car A. 
Test Gear No. 58 jfi-€or 3. 



/mpact Ve/oe/tylJ.08 



tPH 



Ft per sec. 



Ft per sec. 



Ft per sec. 



Ft per sec 



Figure 
68e 



I 



05 



JO 



JS 



.20 



.25 



30 



35 



40 



Test Sear No. 59 //? Cor A 
Test Gear No. 58 In Car B. 
Impact \&/oc/ty=t.84MPtt. 




.05 JO J5 

-0/75 Sec. Geor Compression 



0.356 Sec. Draft Geor Cyc/e 



Dotted lines represent instantaneous car velocities as d< 
termined from the original car-movement curves. 



The irregularities are due in general to vibrations of the 
car structure induced by draft gear action. 
Full lines represent the mean velocity curves. 



Figs. 88e and 88f — Velocity Curves, A. R. A. Class G Springs 



Draft Gear Tests of the U. S. Railroad Administration 



263 



60r 



7esr Gear No. 59 /n Car A 
lest Gear No. 56 in Car 3 
/mpact Ve/oc/ty~/.S3M.RH. 




Time — Seconds 



Full lines represent the instantaneous kinetic energy of 
the moving cars. 



Dotted lines represent the energy stored and absorbed 
during the draft gear cycle. 



Fig. 88j— Energy Curve, A. R. A. Class G Springs 



soft 



400 



Test Gear No. 59 /r? Car A. 
Test Gear No. 58 //? Car 3. 
/mpaot Ve/oc/ty=/.84 MPH 



300 



200 



too 




05 ./0 JS 

—0/75 Sec Gear Compress/on 



0.356 Sec. Draft Gear Cyc/e 



45 



Fig. 88m — Time-Force Curve, A. R. A. Class G Springs 



264 Draft Gear Tests of the U. S. Railroad Administration 













TesT Gear No. 59 in Car A 

Test Gear No 56 /n CarB 

/mpact Vehcffv = /.06 M.RH. 


























D 


















































figure 
Sdp 


.05 JO ./S 
. n/rt -Sec Gear Compression 


.20 25 .30 .3 
/->/-»« Sec. Goon Re/ease. 


5 40 .46 


- — 0. 


342 Se 


c. Drcrfr Gear- Cyc/» 






77me — Seconds 



Curve D, determined from superimposed car-movement 
curves, represents combined draft gear movement and yield 
of car bodies. 

Curve C, obtained by eliminating car body yield from 
curve D, represents true combined movement of both gears. 



represents movement of 



Curve B, traced on small drum, 
gear in Car B. 

Curve A, derived from curves C and B, represents simul- 
taneous movement of gear in Car A. 



Figs 88p and 



-Time-Closure Curves, A. R. A. Class G Springs 



Draft Gear Tests of the U. S. Railroad Administration 265 



soo 

400 



-/.94 1 



Test Gear No. 5^ 7/7 Car A. 



Test Gear No. 58 /n Car 3. 



300 



fmpact , Ve/oc/fy=/86 'MP//. 



200 



/oo 



figure 



-60.000* oac 



'-Test Gear No}S8-CbrB 



/ 2 3 

Gear C/osure —/nche& 

Fig. 88t — Force-Closure Diagram, A. R. A. 
Class G Springs 



266 



Draft Gear Tests of the U. 5. Railroad Administration 















































































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268 



Draft Gear Tests of the U. S. Railroad Administration 



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TdL/OU/ - 3JS7S-0/J JOBS) 



APPENDIX A 



REPORT OF DRAFT GEAR TEST MADE ON NORFOLK & WESTERN 
RAILROAD, NOVEMBER 4, 1918 



Object of Test 

This test was conducted for the purpose 
of determining the relative amount of draft 
gear movement when a car having a draft 
gear with an easy compression curve is 
coupled to a car having a draft gear with 
a relatively stiff compression curve, and to 
determine the probable number of foot 
pounds of work done by each when shocks 
occur. The test was made on the Norfolk 
& Western Railroad in a freight run from 
West Roanoke, Va., to Vicker, Va., a dis- 
tance of 38 miles. The test was conducted 
jointly by the Engineer of Tests of the Nor- 
folk & Western Railroad, and the Section 
of Inspection and Tests of the United States 
Railroad Administration, a representative 
of the National Malleable Castings Com- 
pany being present to assist in the handling 
of the recording instruments, which were 
loaned by that company for the purpose of 
making the test. 

Equipment Used 

The train consisted of 44 miscellaneous 
cars, the tonnage being 1,748 tons. From 
West Roanoke to Elliston, over an un- 
dulating grade, it was handled by Norfolk 
& Western locomotives 422 and 1477 
on the head end, the first of these being a 
Class M of 40,000 lb. tractive effort, and 
the second being a Mallet, Class Zla, of 
73,000 lb. tractive effort. At Elliston, the 
foot of an ascending grade of 1.32 per 
cent, the Class M locomotive was put on 
the rear end to act as a pusher, and at 
Christiansburg, the top of the grade, the 



Class M was cut off entirely. From Christ- 
iansburg to Vicker is a descending grade. 

The cars from which the records were 
made were Norfolk & Western 100-ton 
gondolas, empty, being the first and second 
cars in the train. The rear end of the first 
car, Norfolk & Western 100,147, was 
equipped with a Sessions type K draft gear, 
and the coupled head end of the second 
car, Norfolk & Western 101,534, was 
equipped with a National type H-l draft 
gear. Both cars had experimental M.C.B. 
type C couplers, No. 5 contour, and the 
draft gears were especially prepared for 
the test. All slack was eliminated from the 
draft gear attachments. The Sessions K 
gear as it was applied to the car had T 5 g in. 
initial compression, the National type H-l 
gear being applied with but enough initial 
compression to take out all slack. Holes 
were cut in the floors of the cars for the ap- 
plication of the recording devices and for 
observing the action of the draft gears. 

Preparation of Draft Gears 

The Sessions type K gear used was re- 
moved from a Norfolk & Western cabin 
car and was in practically new condition, 
the friction surfaces being worn to a 
smooth bearing, but not enough to remove 
all of the irregularities of manufacture. The 
friction faces were wiped off and the gear 
set up in the 200,000 lb. testing machine 
of the Norfolk & Western Railroad, and 
an attempt made to close it. Repeated 
sticking and bombardment of the gear led 
to the application of a thin coat of tallow 
on the center friction block to enable the 
closing of it in this machine without the 



— 269 — 



270 



Draft Gear Tests of the U. S. Railroad Administration 



necessity of sledging the gear. The clos- 
ing speed was T \ in. per minute. This 
treatment of the gear was necessary also 
to give the easier compression line desired 
for the purpose of the test, since as pre- 
viously stated the primary purpose of the 
test was to observe the action of a stiff 
gear when coupled with an easy 'gear. The 
greased center friction block did not en- 
tirely eliminate sticking of the gear, the 
compression curve shown in Fig. A-2 being 
plotted directly from the readings taken 
from the beam of the static machine after 
a number of preliminary compressions to 
insure uniform action. The dotted com- 
pression line indicated on this curve is 
worked to in this report as the probable 
compression line in a quick closing of the 
gear. 

The National type H-l gear was removed 
from the same car, No. 101,534, to which it 
was reapplied for the test, and after wip- 
ing off the friction wedges to remove coal 
dust which had fallen over the gear while 
cutting the hole in the car floor, the gear 
was run down as far as the 200,000 lb. ma- 
chine would compress it for a number of 
times. The compression curve shown in 
Fig. A-l for this gear was plotted directly 
from the readings taken from the beam of 
the testing machine. It should be noted 
that whereas this gear is designed for a 
total movement of 2% in., it could only be 
compressed to .93 in. in this 200,000 lb. 
machine. The action of this gear in the 
static machine was smooth and regular. 



Recording Apparatus 

The records of coupler or draft gear 
movement were made upon a moving rib- 
bon of paper, one pencil being arranged 
to draw a datum line on the paper and 
with provisions for indenting this datum 
line when desired, as for marking off time 
increments. The pencil recording the draft 
gear action was caused to move to one or 
the other side of the datum line responsive 
to draft gear action in pulling or buffing, 
the recording arm being attached to the 
butt end of the coupler. The original con- 
tinuous records made in this test are on 
file in the office of the Engineer of Tests 
of the Norfolk & Western Railroad, points 
of interest being abstracted as Figs. A-3 to 
A-ll inclusive of this report. 

The connection between the coupler butt 
and the recording pencil was through a 
reducing mechanism, so that the following 
scale should be used for measuring draft 
gear movement on the cards. 

3 3 2 in. offset on record = a /4 in. coupler movement 
5 5 sin. " " = y 2 in. " 

&in. " " =1 in. 

M in. " « = l%'in. 

Hin. " " =2 in. 

The following tabulation gives the rela- 
tive resistance of the two gears used for 
various amounts of travel, the loads being 
those obtained in the static tests and proper 
allowance being made for the initial com- 
pression of the Sessions gear. 



Coupler 


Sessions K Gear with 




Movement 


Greased Center Friction Block 


National HI Gear 


% in. 


10,400 lbs. 


10,400 lbs. 


Mjin. 


20,850 lbs. 


37,850 lbs. 


% in. 


44,000 lbs. 


116,750 lbs. 


.93 in. 


54,000 lbs. 


200,000 lbs. 


1 in. 


59,000 lbs. 


Capacity of testing machine reached at .93 in. 


lV 2 in. 


87,000 lbs. 


travel of National HI gear. 


1% in. 


108,000 lbs. gear solid 





Draft Gear Tests of the U. S. Railroad Administration 271 



The compression curves, Figs. A-l and 
A-2, and the above tabulation, are not to 
be considered as a comparison of the 
normal action of the two gears, as it has 
already been explained that the capacity 
of the Sessions K gear was purposely re- 
duced for the purpose of the test. 

Discussion of Cards 

The portion of the record reproduced 
as Fig. A-3 shows the action of the two 
gears, beginning with the train moving on 
level track and showing the draft gear 
movements when the train was slowed down 
for orders and then accelerated. The rec- 
ord, which should be read from right to 
left, starts with the Sessions K gear com- 
pressed 1 in., the National gear at the same 
time showing % in. of compression. After 
building up the speed again the Sessions 
gear stood at % in. compression and the 
National at % in. 

In Fig. A-4, with the train moving on a 
slight ascending grade, the train was 
brought to a stop for a red signal, the Ses- 
sions gear moving % in. and the National 
% in. On the succeeding start, the Ses- 
sions gear went to 1% in. and the National 
to 1 in. movement. The Sessions gear 
stuck and bombarded at two points during 
this pulling compression. The influence of 
the bombardment of the Sessions gear is 
manifested in the diagram of the National 
gear. 

The card, Fig. A-5, was made when the 
train was slowed down for orders, the Ses- 
sions gear moving % in. and the National 
gear 1 in. The Sessions gear was sticking 
during this part of the diagram. On start- 
ing, the Sessions gear, after sticking one 
time, went to IVi in. and the National to 
% in. From the static cards there were 
required 2,000 ft. lb. of energy to close 
the Sessions gear this 1*4 in., and 2,053 
ft. lb. to close the National gear the % 
in. at the same time. 



The card, Fig. A-6, was produced when a 
stop was made from a slow speed. 

The card, Fig. A-8, was obtained when 
the train passed through a dip in the track 
(Balls Hole) and shows several compres- 
sions of the gears due to the slack running 
in and shows also a quick pulling compres- 
sion of both gears as the locomotive started 
the train up the grade. As the slack ran 
in, the Sessions gear was compressed % 
in. while the National gear was compressed 
if in. It is presumed that the greater 
movement of the National gear was due 
to the Sessions gear sticking. On the suc- 
ceeding pull the Sessions moved 14 in., 
while the National moved % in. On the 
succeeding start, after sticking, the Ses- 
sions gear moved to 1% in., while the Na- 
tional gear stood at 1% in. 

The card, Fig. A-10, was obtained when 
a sudden stop was made with the pusher 
on the rear end of the train, the pusher 
running in the slack against the front en- 
gine. The Sessions' gear went solid, the 
movement being 1% in., while the Na- 
tional gear moved 1^ in. On the suc- 
ceeding start, which was made on the as- 
cending grade, the National gear responded 
immediately to the amount of 1 in. move- 
ment, while the Sessions gear lagged in 
action and finally bombarded to iy 2 in. 
movement. 

Fig. A-ll shows a typical section of 
record obtained going up the hill from 
Elliston to Christiansburg, on a steady pull 
and at comparatively uniform speed. Both 
gears stood at 1% in. movement. 

General 

The National gear used appeared in gen- 
eral to be quicker in movement and more 
responsive to impulses than this particu- 
lar Sessions gear. In pulling, it is almost 
invariably the case that the National gear 
compressed uniformly and gradually, 
while in most instances the Sessions gear 



18 



272 



Draft Gear Tests of the U. S. Railroad Administration 



obtained its final position after one or more 
bombardments. In release both gears re- 
sponded almost instantly, and in the ma- 
jority of cases a quick buff produced har- 
monious action in both gears. It is notice- 
able, however, that on a quick buff the 
National gear, even though having a stiff er 
resistance curve in the static machine, fre- 



quently shows more travel than the Ses- 
sions gear. With a slow buff as in Fig. A-5 
the Sessions acted through a succession of 
bombardments. 

In a continued steady pull, such as repre- 
sented by the lines in Fig. A- 11 the ab- 
sence of see-saw movements of any extent 
was noticeable in both gears. 



Draft Gear Tests of the U. S. Railroad Administration 273 



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Chronographic Records of Draft Gear Action in Train Service, Norfolk & 

Western Railway 



274 Draft Gear Tests of the U. S. Railroad Administration 





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Western Railway 



APPENDIX B 
TESTS OF CAR CONSTRUCTION 



In accordance with recommendations of 
the Committee on Standards, high speed 
impact tests of car construction were made 
by the Inspection and Test Section of the 
United States Railroad Administration at 
the car impact plant of the T. H. Syming- 
ton Company at Rochester, New York, 
February 25 and 26, 1920. 

The following were present during all 
or a portion of these tests : 

B. W. Kadel, assistant engineer, Inspec- 
tion and Test Section, U.S.R.A. 

E. M. Richards, special engineer, Inspec- 
tion and Test Section, U.S.R.A. 

L. H. Schlatter, representing Draft Gear 
Committee, A.R.A. 

J. A. Pilcher, W. J. Robider and John 
McMullen, sub-committee of Car Construc- 
tion Committee, A.R.A. 

J. R. Onderdonk, B. & 0. Railroad. 

L. H. West, Merchants Dispatch Trans- 
portation Company. 

B. B. Milner, New York Central Rail- 
road. 

D. S. Barrows and I. 0. Wright, repre- 
senting the T. H. Symington Company. 

A total of four tests were made: Tests 
1 and 2 to determine the value of the ap- 
plication of metal draft arms for the rein- 
forcement of wood center sills. Tests 3 and 
4 to show the performance of U.S.R.A. cars 
at high impact velocities and to determine 
the relative value, in buffing, of U.S.R.A. 
draft gear attachments having the separate 
rear draft lugs, and of draft gear attach- 
ments having the central back stop casting 
for distributing the impact force to the car 
sills. 



Test No. 1 — Wood Draft Sills 

The first test was of 40-ton box cars with 
wood center sills, using N.Y.C. Car No. 
214,423 as car A (striking car) and N.Y.C. 
car No. 226,768 as car B (struck car). The 
opposing ends of these cars were fitted with 
wood draft sills. 

These cars have two 5 in. x 8 in. center 
sills, two 4!/2 in. x 8 in. side sills and four 
4>y 2 in. x 8 in. intermediate sills, with 
one-piece cast steel body bolsters beneath 
the sills. The draft sills extend from be- 
neath an 8 in. x 8 in. oak end sill back 
to the body bolster, where they abut suit- 
able pads cast to the body bolster. The 
draft sills are doweled and bolted vertically 
to the center sills and end sill. Malleable 
iron tandem cheek plates are bolted to the 
center sills and draft sills, and have lugs 
gained into both the draft sills and the 
center sills. Sub-sills extend from bolster 
to bolster beneath the main center sills and 
these abut suitable pads cast on the body 
bolster. The cars were equipped with tan- 
dem spring draft gears with 5 in. x 7 in. 
old-standard couplers and wrought steel 
riveted yokes. The coupler horn was 
allowed to strike a heavy cast steel striking 
plate, which was bolted to the face of the 
8 in. x 8 in. oak end sill, the buffing force 
on the draft sills thus being limited to the 
resistance of the two Class G springs, viz., 
60,000 lb. The cars had been fitted with 
new sills throughout for the tests, and the 
steel ends had just been applied. The cars 
were loaded with sand to give a total gross 
weight of 123,000 lb. per car, the sand 
being partly frozen in the cars. 



275 



276 



Draft Gear Tests of the U. S. Railroad Administration 



These cars were given tests at successive 
impact speeds of 4 5, 7, 8, 10, 12 and 14 
miles per hour. 

At 7 M.P.H. the coupler heads began to 
scale and continued scaling throughout the 
tests. At 8 M.P.H. the end at the struck 
end of car B began to bulge out and the 
one at the opposite end of car B began to 
bulge in. At 10 M.P.H. the ends of car A 
began to bulge. This bulging increased 
throughout the test for both cars. A slip- 
page of ^ in. could be detected between 
the draft sills and center sills at 5 M.P.H., 
but this did not increase during the re- 
mainder of the test. A slippage of -^ in. 
occurred between the cheek plates and the 
draft sills at 7 M.P.H., but this also did not 
increase as the test proceeded. 

At the conclusion of the test, the strik- 
ing end of car A had bulged 1% m - an d 
the struck end of car B 3% in. The draft 
sills were shattered where they abut the 
bolster, but no breakage of either draft sills 
or center sills occurred. The bolsters slip- 
ped back % m - during the tests and the 
striking castings moved % in. each. The 
coupler carrier irons bent down % in. The 
coupler horns were not noticeably injured 
except for some scaling and the striking 
castings were in good condition. The ends 
of the center sills, after the test, were 
dropped approximately 1 in. each, but as 
this measurement was not checked in ad- 
vance, it is not definitely known that this 
occurred during the test. The ends, how- 
ever, scaled along the bottom edge, which 
indicates that these ends were straightening 
out and allowing the center sills to droop. 
Except for the bulged ends, no particular 
damage to these cars was apparent and 
they were fit for service. 

Test No. 2 — Metal Draft Arms 

The same box cars were then shifted so 
as to bring the opposite ends together and 
test No. 2 made, N.Y.C. car No. 214,423 



now being car B and N.Y.C. car No. 226,- 
768 car A. The opposing ends of the cars 
were equipped with metal draft arms, 
which were built up of angles and channels 
proportioned to just meet A.R.A. re- 
quirements. The design was made by the 
Inspection and Test Section and does not 
represent the particular details of any pro- 
prietary device. The metal arm did not 
abut the bolsters, but a gusset plate was 
riveted to the top flange of the bolster and 
to the bottom flange of the draft sill angle, 
these angles extending back 5 ft. over the 
bolster towards the center of the car. The 
tandem cheek plates were riveted to a 
channel below the main draft arm angles, 
there being no stop lugs on these cheek 
plates. The coupler horn was allowed to 
strike as in the previous test, the striking 
casting, however, being of malleable iron 
instead of cast steel. The load on the draft 
arms at the center line of the coupler was 
thus limited, as before, to the resistance of 
the two Class G springs. 

These cars were given tests at successive 
speeds of 5, 6, 10, 12, 14 and 16 miles per 
hour. 

At 10 M.P.H. the coupler heads were 
scaling and this scaling continued through- 
out the test. At 10 M.P.H. also the ends of 
the center sills began to droop slightly and 
at the end of the tests had drooped % in. 
on car A and % in. on car B. No bulging 
of the ends occurred during this test, al- 
though the drooping of the sills appeared 
to result from a straightening of the trans- 
verse corrugations of the ends. 

At the 16 M.P.H. run one of the cast 
steel body bolsters was broken transversely, 
one center sill was broken an car B and 
both center sills broken on car A. The 
center sill breakage in each instance oc- 
curred over the bolster, the crack develop- 
ing from the top of the sill. No slippage 
of cheek plates occurred, but the draft 
arms as a whole moved an average of % 



Draft Gear Tests of the U. S. Railroad Administration 



277 



in. with respect to the center sills. The 
coupler carrier irons were bent down ■£$ in. 
and the striking castings moved T 3 g in. on 
the draft arms. 

The performance of the cars in both the 
foregoing tests was unexpectedly good. In 
each instance after the 14 M.P.H. test both 
cars were fit for service, the breakage of 
sills and bolster occurring at the 16 M.P.H. 
run. The fitting up of the wood draft sills 
was an especially good job and it is quite 
probable that extended service would pro- 
duce looseness, which would not be the 
case with metal draft arms. In the limited 
number of tests made it was observed that 
neither type of construction had an especial 
advantage over the other. No pulling tests 
were made, nor was it practical to make a 
considerable number of lower speed im- 
pacts, which unquestionably would have 
produced failure. The comparative merits 
of the two types of construction, however, 
are believed to be indicated by these tests 
at regularly increasing speeds. 

The results of these tests show the fol- 
lowing: 

1. That metal draft arms do not offer 
any noticeable advantage, in buffing, over 
properly applied wood draft arms if the 
latter are kept tight. 

2. It should be observed that the sill 
breakage occurred in each instance over 
the body bolster, although the application 
of the present A.R.A. rule would indicate 
that the unreinforced wood center sill be- 
tween the bolsters is of less value than the 
same sills reinforced over the bolster. 

3. That it is permissible to allow the 
coupler horn to strike in wood car con- 
struction and probably so in steel cars with 
wood end sills. 

4. That there is a pronounced downward 
force at the coupler carry iron and an up- 
ward force at the bolster which may result 
in deformation or breakage at both points. 
As both these forces must be added to the 



static load, cars should be constructed with 
bolsters rigid enough to resist the upward 
tendency, and the end sill and carry iron 
should be securely tied to the end of the 
car. 

Test No. 3 — Draft Attachments with 
Central Stop Casting 

For this test two 70-ton U.S.R.A. low 
side gondola cars were used, P. & R. car 
7378 being car A and P. & R. car 7379 
being car B. These cars have fish belly 
center sills with steel sides, steel plates, 
drop ends and wooden floor. Each car was 
loaded with sand to give a total gross load 
of 184,000 lb. per car, the sand being 
partly frozen in the cars. 

The cars were new and had been equip- 
ped with Farlow 2-key draft gear attach- 
ments, T. H. Symington Company's Print 
F-2437. Flat face dummy couplers' were 
used instead of the regular couplers. There 
being no coupler horns, the entire blow was 
taken through the draft gear attachments. 
Steel blocks of 54 sq. in. cross section were 
used instead of draft gears, the full load 
being taken through this block and being 
delivered upon the back stop casting 
through the intervening parts of the at- 
tachments. The second key had % in - 
clearance in the cheek plate key slot. The 
coupler shanks were made of an extra 
heavy design so as to reduce as far as prac- 
ticable the deformation and failure of this 
part. The net areas of the several parts in 
buffing are as follows: 

Dummy coupler shank, back of head, 24 
sq. in. cast steel. 

Dummy coupler shank at key slot, 171/2 
sq. in. cast steel. (Note — For reference, 
the type D coupler has an area of 16.9 sq. 
in. back of the head, and 13.4 sq. in. at key 
slot.) 

Front follower block, 17*4 sq. in. mal- 
leable iron. 



278 



Draft Gear Tests of the U. S. Railroad Administration 



Rear follower block, 17% sq. in. mal- 
leable iron. 

Yoke, I14 in. x 5% in. (section), 33% 
sq. in. bearing area against back stop. 

Back stop casting, 19% SC I- in., cast steel. 

Back stop casting, 38 rivets through 
center sills and 4 rivets through bottom 
bolster tie plate, all rivets % in., total of 
25.2 sq. in. in shear. 

Keys, 1% i n « x 6 in. 

Malleable iron cheek plates, fourteen % 
in. rivets each. 

The cars were given tests at successive 
speeds of 4, 5, 6, 8, 10, 12 and 14 miles 
per hour. 

At 6 M.P.H. the couplers started to scale 
and deform at the key slots, this deforma- 
tion continuing throughout the test. At 8 
M.P.H. the front portions of the back stop 
castings showed slight scaling. At 10 
M.P.H. this scaling became pronounced 
and continued throughout the remainder of 
the test. At 10 M.P.H., also, three rivets 
at one diagonal brace sheared off and 
others of these rivets had loosened. 

At the conclusion of these tests the fol- 
lowing conditions were found: 

Condition of Cars 

The opposing drop ends of the cars had 
bulged out, both at the top and bottom. In 
car A the bulging amounted to 3% in. at 
the top and 2% in. at the bottom. In car 
B it amounted to 1% in. at the top and % 
in. at the bottom. On both cars the corner 
posts, which are formed of heavy bent 
plates and serve as stops for the ends, were 
bent from the impact of the load. The up- 
standing legs of the end sill angles were 
also bent out from this same force. 

On both cars the body bolsters at the 
opposing ends of the cars were bent down 
at the ends, equivalent to the centers of 
the bolsters being forced upward. In car 
A the center sills were also bent slightly 



from this same condition. The entire ends 
of the cars were down 1 T % in. for car A 
and T 5 e in. for car B. The end sill of car 
A was bowed inward % in. and that of car 
B, 1 in. Neither of the end sills were 
bowed down. 

On car B one of the diagonal braces was 
sheared and torn loose and all diagonal 
braces were either scaling or had loose 
rivets. The floor boards of both cars had 
shifted 1% in. and the floor clips were dis- 
placed. These floor clips began to drop off 
early in the test and do not appear to be a 
satisfactory type of construction. The floor 
boards of both cars were crushed at the 
bolsters and at the end sills from shifting. 
One intermediate wood sill of car A was 
shattered from the same cause. 

At two points on the bolsters of car A 
cracks developed at rivet holes through the 
flanged bolster webs. These cracks re- 
sulted from the horizontal bending of the 
bolster when the sides of the car attempted 
to run ahead of the center sill. No spread- 
ing of the center sills occurred. 

Condition of Coupler and Draft 
Attachments 

Dummy Couplers, cast steel — Shank 
bent both vertically and laterally, and 
upset and deformed at key slots. Short- 
ened an average of % in. each. 

Cheek Plates, malleable iron — No fail- 
ure or injury of any kind. Second key had 
been bearing slightly, indicating momen- 
tary elastic compression of parts. 

Back Stop Castings, cast steel — Slipped 
on rivets 3/64 in. Front end upset 7/64 
in. Not injured perceptibly and removal 
or repairs unnecessary, except that two 
rivet heads jumped off at the final run. 

Yokes, wrought steel— No failure or in- 
jury of any kind. 

Coupler Keys, wrought steel — Not bent 
or injured. 



Draft Gear Tests of the U. S. Railroad Administration 



279 



Second Keys, wrought steel — Bent an 
average of 3 \ in. each. Serviceable with- 
out repairs. 

Front Follower Blocks, malleable iron — 
Shortened ■£■$ in. Not injured perceptibly. 
No repairs necessary. 

Rear Follower Blocks, malleable iron — 
Shortened 3V in. Not injured perceptibly. 
No repairs necessary. 

In this test the cars suffered more than 
the draft gear attachments. It is noticeable 
that not a single part of the attachments 
was damaged to an extent requiring re- 
moval or repairs during this test, and that 
the draft gear pockets had elongated but 
r /V in. each. 

The car damage was greater to car A 
(striking car) than to car B (standing 
car). The back stop castings of the attach- 
ments first beginning to scale at 8 M.P.H. 
this point is taken as the comparative crit- 
ical speed for these attachments, and a 
value of 64, or the square of 8, is accord- 
ingly set for these attachments. 

Test No. 4 — Attachments with Sep- 
arate and Independent Draft Lugs 

Two of the U.S.R.A. 70-ton low side 
gondolas were used for this test, the cars 
being new and having the regular U.S.R.A. 
cast steel yoke and draft gear attachments. 
P. & R. car 7381 was used as car A and 
P. & R. car 7380 as car B. Each car was 
loaded with sand to give a total gross load 
of 184,000 lb. per car, the sand being 
partly frozen in the cars. 

These cars have the regular front and 
rear cast steel draft lugs riveted to the cen- 
ter sills, the rear lugs each having twelve 
% in. rivets and the front lugs ten % in. 
rivets, and three % in. rivets each. The 
rear draft lugs, from the drawings, extend 
to within *4 in. of the bolster center cast- 
ing, which has twelve % in. rivets through 
the center sills and four % in. rivets 
through the bottom bolster tie plate. The 



same steel blocks of 54 sq. in. cross section 
were used instead of draft gears, as in the 
previous test, there being the regular 2 1 / 4z 
in. followers in front of and behind these 
blocks, bearing upon the stop faces of the 
draft lugs. The net bearing area of the 
followers upon the two lugs, in buffing, is 
50 sq. in. The lugs are ribbed to support 
this bearing surface. A tie plate extends 
across the bottom flanges of the center sills 
beneath the draft lugs to reduce the spread- 
ing tendency of the sills from the eccentric 
loading upon the lugs. Dummy couplers 
with flat buffing faces were used in these 
tests, these being duplicates in every re- 
spect of those used in test No. 3. The full 
buffing force was delivered as before, 
through the steel block to the rear stops. 

The cars were given tests at successive 
speeds of 4, 5, 6, 8, 10, 12 and 14 miles per 
hour. 

At 6 M.P.H. the dummy couplers began 
to scale at the key slots, and scaling and 
deformation at this point continued 
throughout the tests. At 8 M.P.H. the op- 
posing ends of the cars were bulged. At 
10 M.P.H. the body bolsters were bent 
slightly. 

At 5 M.P.H. the rear lugs had slipped 
Yg in. on the sills and the stop faces had 
begun to deform. At 6 M.P.H. the lugs 
had bent and pulled away from the center 
sills % in. and the draft gear pockets had 
elongated ■£$ in. This bending and defor- 
mation of the draft lugs increased as the 
test proceeded, and at the 14 M.P.H. run 
both of the lugs of car A, and also the 
bolster center casting, were sheared off and 
driven back between the sills; the truck 
center pin also sheared off. From this 
failure the dummy coupler of car A was 
also driven back, bending the carrier iron 
and carrier iron bolt, and breaking the 
striking casting. The coupler key was bent 
and the front draft lugs broken away, the 
key being driven back through the webs 



280 



Draft Gear Tests of the U. S. Railroad Administration 



of the center sills for 3y 2 in. On car B 
one of the rear draft lugs broke at the 12 
M.P.H. run, but these lugs were not sheared 
off, although they slipped on the rivets % 
in. each. At 8 M.P.H. the rear followers 
had bent 14 in. each, bending the draft lug 
faces also and slightly deforming the webs 
of the center sills. 

At the conclusion of the tests the follow- 
ing conditions were found: 

Condition of Cars 

The drop ends at the opposing ends of 
the cars were bulged, that of car A being 
bulged 3 in. at the top and 2% in. at the 
bottom. In car B this bulging amounted to 
4 in. at the top and 1% in. at the bottom. 
The corner posts were bent as in test No. 3, 
as well as the upstanding legs of the end 
sill angles. The ends of the bolsters were 
bent downward % in. in car A and •(§ in. 
in car B. The sills were slightly bent in 
front of the bolster, the effect being as 
though the center of the bolster was forced 
upward. On car A the bolster center cast- 
ing was driven back and on car B it had 
slipped y 8 in. on the rivets. The end sills 
were not bowed downward, but were bowed 
inward an average of % in. The center sills 
were pushed through the cars an average 
of -f-Q in., the diagonal braces being in bet- 
ter condition than in test No. 3, although 
they showed evidence of failure and loose 
rivets. The floor boards shifted as in the 
previous test and the floor clips loosened. 

The center sills of car B were buckled 
% in. at the bottom flange near the rear 
draft lugs, those of car A being buckled % 
in. -The sills were spread an average of ^ 
in. at the rear draft lugs. The bending of 
the body bolsters reduced the total side 
bearing clearance of each of the trucks at 
the opposing ends of the cars by ■£$ in. 
During the test the draft gear pocket of car 
B was elongated % in. and that of car A 
was entirely destroyed. 



Condition of Coupler and Attachments 

Dummy Couplers, cast steel — Shanks 
bent both vertically and laterally, and 
upset and deformed at key slots. Short- 
ened an average of % in. each. 

Front Draft Lugs — Destroyed in car A. 
Not injured in car B. 

Rear Draft Lugs — Destroyed in both 
cars. 

Cast Steel Yokes — Not injured. (Note 
— These yokes do not come into action in 
buffing.) 

Coupler Keys — Badly bent in car A; re- 
quired to be burnt out. Not injured in 
car B. 

Front Followers — Not injured. 

Rear Followers — Bent % in. in car B. 
Badly bent in car A. Can be repaired. 

Bolster Center Casting — On car B slip- 
ped y 8 in. on rivets. On car A sheared off 
and bent. Can be straightened and reap- 
plied. 

Truck Center Pin — Sheared off. Cannot 
be used. 

Striking Plate — Broken. Can be used. 

Carrier Iron — Bent. Can be used. 

Carrier Iron Bolt — Bent. Cannot be 
used. 

In test No. 4 the greatest injury was to 
the draft gear attachments, the majority of 
parts requiring removal and renewal. Both 
cars were in bad order after the tests. The 
damage to the attachments was greater for 
car A than for car B, while the car damage 
was probably greater for car B. 

The rear lugs of this form of attachment 
having begun to deform at 5 M.P.H. and to 
actually bend away from the sills at 6 
M.P.H., the greatest critical speed that can 
be set for them is 6 M.P.H., or a relative 
value of 36, as compared with 64 for the 
Farlow attachments used in test No. 3. In 
basing relative values upon the square of 
the speeds, it should be remembered that 
the energy is proportional to the square of 
the speed, or, in other words, that a car 



Draft Gear Tests of the U. S. Railroad Administration 281 



moving at ten miles per hour will roll four 
times as far as one moving at five miles per 
hour. An experienced car rider has an in- 
stinctive knowledge of this fact in its rela- 
tion to the kinetic energy of the car, as 
exhibited by the force with which he ap- 
plied the brakes under varying speeds. 

In these tests, as in tests Nos. 1 and 2, it 
is unquestionable that a repetition of im- 
pacts at lower speeds would have produced 
failure, but, as before, it is believed the 
results obtained in these tests represent the 
comparative value of the two forms of at- 
tachments, namely, that the Farlow attach- 
ments as tested showed approximately 
twice the buffing value of the cast steel yoke 
and lug attachments: 

From the results of the test it is apparent : 
1. That the buffing force should be dis- 
tributed to the car sills through a back stop 
casting bridging between the sills, rather 



than upon independent draft lugs riveted to 
each sill. 

2. That if the draft gear is to be pro- 
tected by allowing a front key to strike, 
there should be substantial members on the 
sills for stopping the key. 

3. That in car construction it is neces- 
sary to. give consideration to the results of 
impact when designing the body bolster for 
vertical loads. 

4. That it is important properly to 
anchor the car floor and superstructure to 
the center sills in order properly to impart 
motion to the lading from the center sills. 

5. That in cars with wood floors, or open 
type floors such as hopper cars, particular 
attention should be given to the diagonal 
braces in order that the car sides and center 
sills may be held from independent move- 
ment. 



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